Spiro 2,4-pyrimidinediamine compounds and their uses

ABSTRACT

The present invention provides methods of treating or preventing autoimmune diseases with spiro 2,4-pyrimidinediamine compounds, as well as methods of treating, preventing or ameliorating symptoms associated with such diseases. Specific examples of autoimmune diseases that can be treated or prevented with the compounds include rheumatoid arthritis and/or its associated symptoms, systemic lupus erythematosis and/or its associated symptoms and multiple sclerosis and/or its associated symptoms.

1. CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 U.S.C. § 119(e) to application Ser. No. 60/630,808, filed Nov. 24, 2004, the content of which is incorporated herein by reference.

2. FIELD

The present invention relates generally to spiro 2,4-pyrimidinediamine compounds, pharmaceutical compositions comprising the compounds, intermediates and synthetic methods of making the compounds and methods of using the compounds and compositions in a variety of contexts, such as in the treatment or prevention of autoimmune diseases and/or the symptoms associated therewith.

3. BACKGROUND

Crosslinking of Fc receptors, such as the high affinity receptor for IgE (FcεRI) and/or the high affinity receptor for IgG (FcγRI) activates a signaling cascade in mast, basophil and other immune cells that results in the release of chemical mediators responsible for numerous adverse events. For example, such crosslinking leads to the release of preformed mediators of Type I (immediate) anaphylactic hypersensitivity reactions, such as histamine, from storage sites in granules via degranulation. It also leads to the synthesis and release of other mediators, including leukotrienes, prostaglandins and platelet-activating factors (PAFs), that play important roles in inflammatory reactions. Additional mediators that are synthesized and released upon crosslinking Fc receptors include cytokines and nitric oxide.

The signaling cascade(s) activated by crosslinking Fc receptors such as FcεRI and/or FcγRI comprises an assay of cellular proteins. Among the most important intracellular signal propagators are the tyrosine kinases. And, an important tyrosine kinase involved in the signal transduction pathways associated with crosslinking the FcεRI and/or FcγRI receptors, as well as other signal transduction cascades, is Syk kinase (see Valent et al., 2002, Intl. J. Hematol. 75(4):257-362 for review).

As the mediators released as a result of FcεRI and FcγRI receptor cross-linking are responsible for, or play important roles in, the manifestation of numerous adverse events, the availability of compounds capable of inhibiting the signaling cascade(s) responsible for their release would be highly desirable. Moreover, owing to the critical role that Syk kinase plays these and other receptor signaling cascade(s), the availability of compounds capable of inhibiting Syk kinase would also be highly desirable.

4. SUMMARY

In one aspect, the present invention provides novel spiro 2,4-pyrimidinediamine compounds that, as will be discussed in more detail below, have myriad biological activities. The compounds generally comprise a 2,4-pyrimidinediamine “core” having the following structure and numbering convention:

The compounds described herein are substituted at the C2 nitrogen (N2) and C4 nitrogen (N4) to form two secondary amines and are optionally further substituted at one or more of the following positions: the C5 position and/or the C6 position. The substituent at N2, as well as the optional substituents at the other positions, other than N4, may range broadly in character and physico-chemical properties. For example, the substituent(s) may be a branched, straight-chained or cyclic alkyl, a branched, straight-chained or cyclic heteroalkyl, a mono- or polycyclic aryl a mono- or polycyclic heteroaryl or combinations of these groups. These substituent groups may be further substituted, as will be described in more detail below. The N4 substituent will generally contain a spiro heterocyclic group as described, infra.

The N2 and/or N4 substituents may be attached directly to their respective nitrogen atoms, or they may be spaced away from their respective nitrogen atoms via linkers, which may be the same or different. The nature of the linkers can vary widely, and can include virtually any combination of atoms or groups useful for spacing one molecular moiety from another. For example, the linker may be an acyclic hydrocarbon bridge (e.g., a saturated or unsaturated alkyleno such as methano, ethano, etheno, propano, prop[1]eno, butano, but[1]eno, but[2]eno, buta[1,3]dieno, and the like), a monocyclic or polycyclic hydrocarbon bridge (e.g., [1,2]benzeno, [2,3]naphthaleno, and the like), a simple acyclic heteroatomic or heteroalkyldiyl bridge (e.g., —O—, —S—, —S—O—, —NH—, —PH—, —C(O)—, —C(O)NH—, —S(O)—, —S(O)₂—, —S(O)NH—, —S(O)₂NH—, —O—CH₂—, —CH₂—O—CH₂—, —O—CH═CH—CH₂—, and the like), a monocyclic or polycyclic heteroaryl bridge (e.g., [3,4]furano, pyridino, thiopheno, piperidino, piperazino, pyrazidino, pyrrolidino, and the like) or combinations of such bridges.

The substituents at the N2, N4, C5 and/or C6 positions, as well as the optional linkers, may be further substituted with one or more of the same or different substituent groups. The nature of these substituent groups may vary broadly. Non-limiting examples of suitable substituent groups include branched, straight-chain or cyclic alkyls, mono- or polycyclic aryls, branched, straight-chain or cyclic heteroalkyls, mono- or polycyclic heteroaryls, halos, branched, straight-chain or cyclic haloalkyls, hydroxyls, oxos, thioxos, branched, straight-chain or cyclic alkoxys, branched, straight-chain or cyclic haloalkoxys, trifluoromethoxys, mono- or polycyclic aryloxys, mono- or polycyclic heteroaryloxys, ethers, alcohols, sulfides, thioethers, sulfanyls (thiols), imines, azos, azides, amines (primary, secondary and tertiary), nitriles (any isomer), cyanates (any isomer), thiocyanates (any isomer), nitrosos, nitros, diazos, sulfoxides, sulfonyls, sulfonic acids, sulfamides, sulfonamides, sulfamic esters, aldehydes, ketones, carboxylic acids, esters, amides, amidines, formadines, amino acids, acetylenes, carbamates, lactones, lactams, glucosides, gluconurides, sulfones, ketals, acetals, thioketals, oximes, oxamic acids, oxamic esters, etc., and combinations of these groups. Substituent groups bearing reactive functionalities may be protected or unprotected, as is well-known in the art.

In one illustrative embodiment, the spiro 2,4-pyrimidinediamine compounds described herein are compounds according to structural formula (I):

including salts, hydrates, solvates and N-oxides thereof, wherein:

L¹ is a direct bond or a linker;

L² is a direct bond or a linker;

R² is selected from the group consisting of (C1-C6) alkyl optionally substituted with one or more of the same or different R⁸ groups, (C3-C8) alkyl optionally substituted with one or more of the same or different R⁸ groups, 3-8 membered cycloheteroalkyl optionally substituted with one or more of the same or different R⁸ groups, (C5-C15) aryl optionally substituted with one or more of the same or different R⁸ groups, phenyl optionally substituted with one or more of the same or different R⁸ groups and 5-15 membered heteroaryl optionally substituted with one or more of the same or different R⁸ groups;

R⁴ is

each W is, independently of the other, —CR³¹R³¹—;

X is selected from the group consisting of —N— and —CH—;

Y and Z are each, independently of one another, selected from the group consisting of —O—, —S—, —SO—, —SO₂—, —SONR³⁶—, —NH—, —NR³⁵— and —NR³⁷—;

R⁵ is selected from the group consisting of hydrogen, an electronegative group, —OR^(d), —SR^(d), (C1-C3) haloalkyloxy, (C1-C3) perhaloalkyloxy, —NR^(c)R^(c), halogen, (C1-C3) haloalkyl, (C1-C3) perhaloalkyl, —CF₃, —CH₂CF₃, —CF₂CF₃, —CN, —NC, —OCN, —SCN, —NO, —NO₂, —N₃, —S(O)R^(d), —S(O)₂R^(d), —S(O)₂OR^(d), —S(O)NR^(c)R^(c); —S(O)₂NR^(c)R^(c), —OS(O)R^(d), —OS(O)₂R^(d), —OS(O)₂OR^(d), —OS(O)NR^(c)R^(c), —OS(O)₂NR^(c)R^(c), —C(O)R^(d), —C(O)OR^(d), —C(O)NR^(c)R^(c), —C(NH)NR^(c)R^(c), —OC(O)R^(d), —SC(O)R^(d), —OC(O)OR^(d), —SC(O)OR^(d), —OC(O)NR^(c)R^(c), —SC(O)NR^(c)R^(c), —OC(NH)NR^(c)R^(c), —SC(NH)NR^(c)R^(c), —[NHC(O)]_(n)R^(d), —[NHC(O)]_(n)OR^(d), —[NHC(O)]_(n)NR^(c)R^(c) and —[NHC(NH)]_(n)NR^(c)R^(c), (C5-C10) aryl optionally substituted with one or more of the same or different R⁸ groups, phenyl optionally substituted with one or more of the same or different R⁸ groups, (C6-C16) arylalkyl optionally substituted with one or more of the same or different R⁸ groups, 5-10 membered heteroaryl optionally substituted with one or more of the same or different R⁸ groups and 6-16 membered heteroarylalkyl optionally substituted with one or more of the same or different R⁸ groups, (C1-C6) alkyl optionally substituted with one or more of the same or different R⁸ groups, (C1-C4) alkanyl optionally substituted with one or more of the same or different R⁸ groups, (C2-C4) alkenyl optionally substituted with one or more of the same or different R⁸ groups and (C2-C4) alkynyl optionally substituted with one or more of the same or different R⁸ groups;

R⁶ independently is selected from the group consisting of hydrogen, an electronegative group, —OR^(d), —SR^(d), (C1-C3) haloalkyloxy, (C1-C3) perhaloalkyloxy, —NR^(c)R^(c), halogen, (C1-C3) haloalkyl, (C1-C3) perhaloalkyl, —CF₃, —CH₂CF₃, —CF₂CF₃, —CN, —NC, —OCN, —SCN, —NO, —NO₂, —N₃, —S(O)R^(d), —S(O)₂R^(d), —S(O)₂OR^(d), —S(O)NR^(c)R^(c); —S(O)₂NR^(c)R^(c), —OS(O)R^(d), —OS(O)₂R^(d), —OS(O)₂OR^(d), —OS(O)NR^(c)R^(c), —OS(O)₂NR^(c)R^(c), —C(O)R^(d), —C(O)OR^(d), —C(O)NR^(c)R^(c), —C(NH)NR^(c)R^(c), —OC(O)R^(d), —SC(O)R^(d), —OC(O)OR^(d), —SC(O)OR^(d), —OC(O)NR^(c)R^(c), —SC(O)NR^(c)R^(c), —OC(NH)NR^(c)R^(c), —SC(NH)NR^(c)R^(c), —[NHC(O)]_(n)R^(d), —[NHC(O)]_(n)OR^(d), —[NHC(O)]_(n)NR^(c)R^(c) and —[NHC(NH)]_(n)NR^(c)R^(c), (C5-C10) aryl optionally substituted with one or more of the same or different R⁸ groups, phenyl optionally substituted with one or more of the same or different R⁸ groups, (C6-C16) arylalkyl optionally substituted with one or more of the same or different R⁸ groups, 5-10 membered heteroaryl optionally substituted with one or more of the same or different R⁸ groups and 6-16 membered heteroarylalkyl optionally substituted with one or more of the same or different R⁸ groups;

R⁸ is selected from the group consisting of R^(a), R^(b), R^(a) substituted with one or more of the same or different R^(a) or R^(b), —OR^(a) substituted with one or more of the same or different R^(a) or R^(b), —B(OR^(a))₂, —B(NR^(c)R^(c))₂, —(CH₂)_(m)—R^(b), —(CHR^(a))_(m)—R^(b), —O—(CH₂)_(m)—R^(b), —S—(CH₂)_(m)—R^(b), —O—CHR^(a)R^(b), —O—CR^(a)(R^(b))₂, —O—(CHR^(a))_(m)—R^(b), —O—(CH₂)_(m)—CH[(CH₂)_(m)R^(b)]R^(b), —S—(CHR^(a))_(m)—R^(b), —C(O)NH—(CH₂)_(m)—R^(b), —C(O)NH—(CHR^(a))_(m)—R^(b), —O—(CH₂)_(m)—C(O)NH—(CH₂)_(m)—R^(b), —S—(CH₂)_(m)—C(O)NH—(CH₂)_(m)—R^(b), —O—(CHR^(a))_(m)—C(O)NH—(CHR^(a))_(m)—R^(b), —S—(CHR^(a))_(m)—C(O)NH—(CHR^(a))_(m)—R^(b), —NH—(CH₂)_(m)—R^(b), —NH—(CHR^(a))_(m)—R^(b), —NH[(CH₂)_(m)R^(b)], —N[(CH₂)_(m)R^(b)]₂, —NH—C(O)—NH—(CH₂)_(n)—R^(b), —NH—C(O)—(CH₂)_(m)—CHR^(b)R^(b) and —NH—(CH₂)_(n)—C(O)—NH—(CH₂)_(m)—R^(b);

each R³¹ is, independently of the others, hydrogen or (C1-C6) alkyl optionally substituted with one or more of the same or different R⁸ groups;

each R³⁵ is, independently of the other, selected from the group consisting of hydrogen and R⁸, or, alternatively, the two R³⁵ groups are taken together to form an oxo (═O), or ═NR³⁸ group;

each R³⁶ is, independently of the others, selected from the group consisting of hydrogen and (C1-C6) alkyl;

each R³⁷ is, independently of the others, selected from the group consisting of hydrogen and a progroup;

R³⁸ is selected from the group consisting of hydrogen, (C1-C6) alkyl and (C5-C14) aryl;

each R^(a) is, independently of the others, selected from the group consisting of hydrogen, (C1-C6) alkyl, (C3-C8) cycloalkyl, cyclohexyl, (C4-C11) cycloalkylalkyl, (C5-C10) aryl, phenyl, (C6-C16) arylalkyl, benzyl, 2-6 membered heteroalkyl, 3-8 membered cycloheteroalkyl, morpholinyl, piperazinyl, homopiperazinyl, piperidinyl, 4-11 membered cycloheteroalkylalkyl, 5-10 membered heteroaryl and 6-16 membered heteroarylalkyl;

each R^(b) is, independently of the others, a suitable group independently selected from the group consisting of ═O, —OR^(d), (C1-C3) haloalkyloxy, —OCF₃, ═S, —SR^(d), ═NR¹, ═NOR^(d), —NR^(c)R^(c), halogen, —CF₃, —CN, —NC, —OCN, —SCN, —NO, —NO₂, ═N₂, —N₃, —S(O)R^(d), —S(O)₂R^(d), —S(O)₂OR^(d), —S(O)NR^(c)R^(c), —S(O)₂NR^(c)R^(c), —OS(O)R^(d), —OS(O)₂R^(d), —OS(O)₂OR^(d), —OS(O)₂NR^(c)R^(c), —C(O)R^(d), —C(O)OR^(d), —C(O)NR^(c)R^(c), —C(NH)NR^(c)R^(c), —C(NR^(a))NR^(c)R^(c), —C(NOH)R^(a), —C(NOH)NR^(c)R^(c), —OC(O)R^(d), —OC(O)OR^(d), OC(O)NR^(c)R^(c), —OC(NH)NR^(c)R^(c), —OC(NR^(a))NR^(c)R^(c), —[NHC(O)]_(n)R^(d), —[NR^(a)C(O)]_(n)R^(d), —[NHC(O)]_(n)OR^(d), —[NR^(a)C(O)]_(n)OR^(d), —[NHC(O)]_(n)NR^(c)R^(c), —[NR^(a)C(O)]_(n)NR^(c)R^(c), —[NHC(NH)]_(n)NR^(c)R^(c) and —[NR^(a)C(NR^(a))]_(n)NR^(c)R^(c);

each R^(c) is, independently or the others, a protecting group or R^(a), or, alternatively, each R^(c) is taken together with the nitrogen atom to which it is bonded to form a 5 to 8-membered cycloheteroalkyl or heteroaryl which may optionally include one or more of the same or different additional heteroatoms and which may optionally be substituted with one or more of the same or different R^(a) or suitable R^(b) groups;

each R^(d) is, independently of the others, a protecting group or R^(a);

each m is, independently of the others, an integer from 1 to 3;

each n is, independently of the others, an integer from 0 to 3; and

o is an integer from 1 to 6.

In one embodiment, R⁵ is F and R⁶ is hydrogen.

In another aspect, prodrugs of the spiro 2,4-pyrimidinediamine compounds are provided. Such prodrugs may be active in their prodrug form, or may be inactive until converted under physiological or other conditions of use to an active drug form. In the prodrugs described herein, one or more functional groups of the spiro 2,4-pyrimidinediamine compounds are included in promoieties that cleave from the molecule under the conditions of use, typically by way of hydrolysis, enzymatic cleavage or some other cleavage mechanism, to yield the functional groups. For example, primary or secondary amino groups may be included in an amide promoiety that cleaves under conditions of use to generate the primary or secondary amino group. Thus, the prodrugs described herein include special types of protecting groups, termed “progroups,” masking one or more functional groups of the spiro 2,4-pyrimidinediamine compounds that cleave under the conditions of use to yield an active spiro 2,4-pyrimidinediamine drug compound. Functional groups within the 2,4-pyrimidinediamine compounds that may be masked with progroups for inclusion in a promoiety include, but are not limited to, amines (primary and secondary), hydroxyls, sulfanyls (thiols), carboxyls, carbonyls, phenols, catechols, diols, alkynes, phosphates, etc. Myriad progroups suitable for masking such functional groups to yield promoieties that are cleavable under the desired conditions of use are known in the art. All of these progroups, alone or in combinations, may be included in the prodrugs of the invention. Specific examples of promoieties that yield primary or secondary amine groups that can be included in the prodrugs of the invention include, but are not limited to amides, carbamates, imines, ureas, phosphenyls, phosphoryls and sulfenyls. Specific examples of promoieties that yield sulfanyl groups that can be included in the prodrugs of the invention include, but are not limited to, thioethers, for example S-methyl derivatives (monothio, dithio, oxythio, aminothio acetals), silyl thioethers, thioesters, thiocarbonates, thiocarbamates, asymmetrical disulfides, etc. Specific examples of promoieties that cleave to yield hydroxyl groups that can be included in the prodrugs of the invention include, but are not limited to, sulfonates, esters and carbonates. Specific examples of promoieties that yield carboxyl groups that can be included in the prodrugs described herein included, but are not limited to, esters (including silyl esters, oxamic acid esters and thioesters), amides and hydrazides.

In one illustrative embodiment, prodrugs include compounds according to structural formula (I) in which the protecting group of R^(c) and R^(d) is a progroup.

In another illustrative embodiment, prodrugs are compounds according to structural formula (II):

including salts, hydrates, solvates and N-oxides thereof, wherein:

R², R⁴, R⁵, R⁶, L¹ and L² are as previously defined for structural formula (I);

R^(2b) is a progroup;

R^(4b) is progroup or an alkyl group, e.g., methyl.

In another aspect, pharmaceutical compositions comprising one or more compounds and/or prodrugs described herein and an appropriate carrier, excipient or diluent are provided. The exact nature of the carrier, excipient or diluent will depend upon the desired use for the composition, and may range from being suitable or acceptable for veterinary uses to being suitable or acceptable for human use.

In still another aspect, intermediates useful for synthesizing the 2,4-pyrimidinediamine compounds and prodrugs described herein are provided. In one embodiment, the intermediates are spiro compounds according to structural formula (III):

including salts, hydrates, solvates and N-oxides thereof, wherein o, W, R³⁵, X, Y and Z are as previously defined for structural formula (I) and D is hydrogen, halogen, —NO₂ or —NH₂.

In another embodiment, the intermediates are 2-4-pyrimidineamines according to structural formula (IV):

including salts, hydrates, solvates and N-oxides thereof, wherein R⁵, R⁶, o, R³¹, R³⁵, X, Y and Z are as previously defined for structural formula (I) and LG is a leaving group, such as, for example, —S(O)₂Me, —SMe or halo (e.g., F, Cl, Br, I).

The spiro 2,4-pyrimidinediamine compounds described herein are potent inhibitors of degranulation of immune cells, such as mast, basophil, neutrophil and/or eosinophil cells. Thus, in still another aspect, methods of regulating, and in particular, inhibiting, degranulation of such cells are provided. The method generally involves contacting a cell that degranulates with an amount of a spiro 2,4-pyrimidinediamine compound or prodrug thereof, or an acceptable salt, hydrate, solvate, N-oxide and/or composition thereof, effective to regulate or inhibit degranulation of the cell. The method may be practiced in in vitro contexts or in in vivo contexts as a therapeutic approach towards the treatment or prevention of diseases characterized by, caused by or associated with cellular degranulation.

While not intending to be bound by any theory of operation, spiro 2,4-pyrimidinediamine compounds may exert their degranulation inhibitory effect, at least in part, by blocking or inhibiting the signal transduction cascade(s) initiated by crosslinking of the high affinity Fc receptors for IgE (“FcεRI”) and/or IgG (“FcγRI”). Indeed, the spiro 2,4-pyrimidinediamine compounds may be inhibitors of both FcεRI-mediated and FcγRI-mediated degranulation. As a consequence, the 2,4-pyrimidine compounds may be used to inhibit these Fc receptor signaling cascades in any cell type expressing such FcεRI and/or FcγRI receptors including but not limited to macrophages, mast, basophil, neutrophil and/or eosinophil cells.

The methods may also permit the regulation of, and in particular the inhibition of, downstream processes that result as a consequence of activating such Fc receptor signaling cascade(s). Such downstream processes include, but are not limited to, FcεRI-mediated and/or FcγRI-mediated degranulation, cytokine production and/or the production and/or release of lipid mediators such as leukotrienes and prostaglandins. The method generally involves contacting a cell expressing an Fc receptor, such as one of the cell types discussed above, with an amount of a spiro 2,4-pyrimidinediamine compound or prodrug thereof, or an acceptable salt, hydrate, solvent, N-oxide and/or composition thereof, effective to regulate or inhibit the Fc receptor signaling cascade and/or a downstream process effected by the activation of this signaling cascade. The method may be practiced in in vitro contexts or in in vivo contexts as a therapeutic approach towards the treatment or prevention of diseases characterized by, caused by or associated with the Fc receptor signaling cascade, such as diseases effected by the release of granule specific chemical mediators upon degranulation, the release and/or synthesis of cytokines and/or the release and/or synthesis of lipid mediators such as leukotrienes and prostaglandins.

In yet another aspect, methods of treating and/or preventing diseases characterized by, caused by or associated with the release of chemical mediators as a consequence of activating Fc receptor signaling cascades, such as FcεRI and/or FcγRI-signaling cascades is provided. The methods may be practiced in animals in veterinary contexts or in humans. The methods generally involve administering to an animal subject or human an amount of a spiro 2,4-pyrimidinediamine compound or prodrug thereof, or an acceptable salt, hydrate, solvate, N-oxide and/or composition thereof, effective to treat or prevent the disease. As discussed previously, activation of the FcεRI or FcγRI receptor signaling cascade in certain immune cells leads to the release and/or synthesis of a variety of chemical substances that are pharmacological mediators of a wide variety of diseases. Any of these diseases may be treated or prevented according to the methods of the invention.

For example, in mast cells and basophil cells, activation of the FcεRI or FcγRI signaling cascade leads to the immediate (i.e., within 1-3 min. of receptor activation) release of preformed mediators of atopic and/or Type I hypersensitivity reactions (e.g., histamine, proteases such as tryptase, etc.) via the degranulation process. Such atopic or Type I hypersensitivity reactions include, but are not limited to, anaphylactic reactions to environmental and other allergens (e.g., pollens, insect and/or animal venoms, foods, drugs, contrast dyes, etc.), anaphylactoid reactions, hay fever, allergic conjunctivitis, allergic rhinitis, allergic asthma, atopic dermatitis, eczema, urticaria, mucosal disorders, tissue disorders and certain gastrointestinal disorders.

The immediate release of the preformed mediators via degranulation is followed by the release and/or synthesis of a variety of other chemical mediators, including, among other things, platelet activating factor (PAF), prostaglandins and leukotrienes (e.g., LTC4) and the de novo synthesis and release of cytokines such as TNFα, IL-4, IL-5, IL-6, IL-13, etc. The first of these two processes occurs approximately 3-30 min. following receptor activation; the latter approximately 30 min.-7 hrs. following receptor activation. These “late stage” mediators are thought to be in part responsible for the chronic symptoms of the above-listed atopic and Type I hypersensitivity reactions, and in addition are chemical mediators of inflammation and inflammatory diseases (e.g., osteoarthritis, inflammatory bowel disease, ulcerative colitis, Crohn's disease, idiopathic inflammatory bowel disease, irritable bowel syndrome, spastic colon, etc.), low grade scarring (e.g., scleroderma, increased fibrosis, keloids, post-surgical scars, pulmonary fibrosis, vascular spasms, migraine, reperfusion injury and post myocardial infarction), and sicca complex or syndrome. All of these diseases may be treated or prevented according to the methods of the invention.

Additional diseases which can be treated or prevented according to the methods described herein include diseases associated with basophil cell and/or mast cell pathology. Examples of such diseases include, but are not limited to, diseases of the skin such as scleroderma, cardiac diseases such as post myocardial infarction, pulmonary diseases such as pulmonary muscle changes or remodeling and chronic obstructive pulmonary disease (COPD) and diseases of the gut such as inflammatory bowel syndrome (spastic colon).

Spiro 2,4-pyrimidinediamine compounds are also potent inhibitors of the tyrosine kinase Syk kinase. Thus, in still another aspect, methods of regulating, and in particular inhibiting, Syk kinase activity are provided. The method generally involves contacting a Syk kinase or a cell comprising a Syk kinase with an amount of a spiro 2,4-pyrimidinediamine compound or prodrug thereof, or an acceptable salt, hydrate, solvate, N-oxide and/or composition thereof, effective to regulate or inhibit Syk kinase activity. In one embodiment, the Syk kinase is an isolated or recombinant Syk kinase. In another embodiment, the Syk kinase is an endogenous or recombinant Syk kinase expressed by a cell, for example a mast cell or a basophil cell. The method may be practiced in in vitro contexts or in in vivo contexts as a therapeutic approach towards the treatment or prevention of diseases characterized by, caused by or associated with Syk kinase activity.

While not intending to be bound by any particular theory of operation, spiro 2,4-pyrimdinediamine compounds may inhibit cellular degranulation and/or the release of other chemical mediators primarily by inhibiting Syk kinase that gets activated through the gamma chain homodimer of FcεRI (see, e.g., FIG. 2). This gamma chain homodimer is shared by other Fc receptors, including FcγRI, FcγRIII and FcαRI. For all of these receptors, intracellular signal transduction is mediated by the common gamma chain homodimer. Binding and aggregation of those receptors results in the recruitment and activation of tyrosine kinases such as Syk kinase. As a consequence of these common signaling activities, the spiro 2,4-pyrimidinediamine compounds described herein may be used to regulate, and in particular inhibit, the signaling cascades of Fc receptors having this gamma chain homodimer, such as FcεRI, FcγRI, FcγRIII and FcαRI, as well as the cellular responses elicited through these receptors.

Syk kinase is known to play a critical role in other signaling cascades. For example, Syk kinase is an effector of B-cell receptor (BCR) signaling (Turner et al., 2000, Immunology Today 21:148-154) and is an essential component of integrin beta(1), beta(2) and beta(3) signaling in neutrophils (Mocsai et al., 2002, Immunity 16:547-558). As the spiro 2,4-pyrimidinediamine compounds described herein are potent inhibitors of Syk kinase, they can be used to regulate, and in particular inhibit, any signaling cascade where Syk plays a role, such as, fore example, the Fc receptor, BCR and integrin signaling cascades, as well as the cellular responses elicited through these signaling cascades. The particular cellular response regulated or inhibited will depend, in part, on the specific cell type and receptor signaling cascade, as is well known in the art. Non-limiting examples of cellular responses that may be regulated or inhibited with the spiro 2,4-pyrimidinediamine compounds include a respiratory burst, cellular adhesion, cellular degranulation, cell spreading, cell migration, phagocytosis (e.g., in macrophages), calcium ion flux (e.g., in mast, basophil, neutrophil, eosinophil and B-cells), platelet aggregation, and cell maturation (e.g., in B-cells).

Thus, in another aspect, methods of regulating, and in particular inhibiting, signal transduction cascades in which Syk plays a role are provided. The methods generally involve contacting a Syk-dependent receptor or a cell expressing a Syk-dependent receptor with an amount of a spiro 2,4-pyrimidinediamine compound or prodrug described herein, or an acceptable salt, hydrate, solvate, N-oxide and/or composition thereof, effective to regulate or inhibit the signal transduction cascade. The methods may also be used to regulate, and in particular inhibit, downstream processes or cellular responses elicited by activation of the particular Syk-dependent signal transduction cascade. The methods may be practiced to regulate any signal transduction cascade where Syk is not known or later discovered to play a role. The methods may be practiced in in vitro contexts or in in vivo contexts as a therapeutic approach towards the treatment or prevention of diseases characterized by, caused by or associated with activation of the Syk-dependent signal transduction cascade. Non-limited examples of such diseases include those previously discussed.

Spiro 2,4-pyrimidinediamine compounds described herein may also be used to treat or prevent autoimmune diseases and/or symptoms of such diseases. The methods generally involve administering to a subject suffering from an autoimmune disease or at risk of developing an autoimmune disease an amount of a spiro 2,4-pyrimidinediamine method or prodrug thereof, or an acceptable salt, N-oxide, hydrate, solvate or composition thereof, effective to treat or prevent the autoimmune disease and/or its associated symptoms. Autoimmune diseases that may be treated or prevented with the spiro 2,4-pyrimidinediamine compounds include those diseases that are commonly associated with nonanaphylactic hypersensitivity reactions (Type II, Type III and/or Type IV hypersensitivity reactions) and/or those diseases that are mediated, at least in part, by activation of the FcγR signaling cascade in monocyte cells. Such autoimmune disease include, but are not limited to, those autoimmune diseases that are frequently designated as single organ or single cell-type autoimmune disorders and those autoimmune disease that are frequently designated as involving systemic autoimmune disorder. Non-limiting examples of diseases frequently designated as single organ or single cell-type autoimmune disorders include: Hashimoto's thyroiditis, autoimmune hemolytic anemia, autoimmune atrophic gastritis of pernicious anemia, autoimmune encephalomyelitis, autoimmune orchitis, Goodpasture's disease, autoimmune thrombocytopenia, sympathetic ophthalmia, myasthenia gravis, Graves' disease, primary biliary cirrhosis, chronic aggressive hepatitis, ulcerative colitis and membranous glomerulopathy. Non-limiting examples of diseases often designated as involving systemic autoimmune disorder include: systemic lupus erythematosis, rheumatoid arthritis, Sjogren's syndrome, Reiter's syndrome, polymyositis-dermatomyositis, systemic sclerosis, polyarteritis nodosa, multiple sclerosis and bullous pemphigoid.

5. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 provides a cartoon illustrating allergen-induced production of IgE and consequent release of preformed and other chemical mediators from mast cells;

FIG. 2 provides a cartoon illustrating the FcεR1 signal transduction cascade leading to degranulation of mast and/or basophil cells; and

FIG. 3 provides a cartoon illustrating the putative points of action of compounds that selectively inhibit upstream FcεRI-mediated degranulation and compounds that inhibit both FcεRI-mediated and ionomycin-induced degranulation.

6. DETAILED DESCRIPTION

6.2 Definitions

As used herein, the following terms are intended to have the following meanings:

“Alkyl” by itself or as part of another substituent refers to a saturated or unsaturated branched, straight-chain or cyclic monovalent hydrocarbon radical having the stated number of carbon atoms (i.e., C1-C6 means one to six carbon atoms) that is derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane, alkene or alkyne. Typical alkyl groups include, but are not limited to, methyl; ethyls such as ethanyl, ethenyl, ethynyl; propyls such as propan-1-yl, propan-2-yl, cyclopropan-1-yl, prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl, cycloprop-1-en-1-yl; cycloprop-2-en-1-yl, prop-1-yn-1-yl, prop-2-yn-1-yl, etc.; butyls such as butan-1-yl, butan-2-yl, 2-methyl-propan-1-yl, 2-methyl-propan-2-yl, cyclobutan-1-yl, but-1-en-1-yl, but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-1-yl, but-2-en-2-yl, buta-1,3-dien-1-yl, buta-1,3-dien-2-yl, cyclobut-1-en-1-yl, cyclobut-1-en-3-yl, cyclobuta-1,3-dien-1-yl, but-1-yn-1-yl, but-1-yn-3-yl, but-3-yn-1-yl, etc.; and the like. Where specific levels of saturation are intended, the nomenclature “alkanyl,” “alkenyl” and/or “alkynyl” is used, as defined below. In some embodiments, the alkanyl groups are (C₁-C₁₀) alkyl. In other embodiments, the alkyl groups are (C₁-C₆) alkyl.

“Alkanyl” by itself or as part of another substituent refers to a saturated branched, straight-chain or cyclic alkyl derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane. Typical alkanyl groups include, but are not limited to, methanyl; ethanyl; propanyls such as propan-1-yl, propan-2-yl (isopropyl), cyclopropan-1-yl, etc.; butanyls such as butan-1-yl, butan-2-yl (sec-butyl), 2-methyl-propan-1-yl (isobutyl), 2-methyl-propan-2-yl (t-butyl), cyclobutan-1-yl, etc.; and the like.

“Alkenyl” by itself or as part of another substituent refers to an unsaturated branched, straight-chain or cyclic alkyl having at least one carbon-carbon double bond derived by the removal of one hydrogen atom from a single carbon atom of a parent alkene. The group may be in either the cis or trans conformation about the double bond(s). Typical alkenyl groups include, but are not limited to, ethenyl; propenyls such as prop-1-en-1-yl, prop-1-en-2-yl, prop-2-en-1-yl, prop-2-en-2-yl, cycloprop-1-en-1-yl; cycloprop-2-en-1-yl; butenyls such as but-1-en-1-yl, but-1-en-2-yl, 2-methyl-prop-1-en-1-yl, but-2-en-1-yl, but-2-en-2-yl, buta-1,3-dien-1-yl, buta-1,3-dien-2-yl, cyclobut-1-en-1-yl, cyclobut-1-en-3-yl, cyclobuta-1,3-dien-1-yl, etc.; and the like. In preferred embodiments, the alkenyl group is (C2-C6) alkenyl.

“Alkynyl” by itself or as part of another substituent refers to an unsaturated branched, straight-chain or cyclic alkyl having at least one carbon-carbon triple bond derived by the removal of one hydrogen atom from a single carbon atom of a parent alkyne. Typical alkynyl groups include, but are not limited to, ethynyl; propynyls such as prop-1-yn-1-yl, prop-2-yn-1-yl, etc.; butynyls such as but-1-yn-1-yl, but-1-yn-3-yl, but-3-yn-1-yl, etc.; and the like.

“Alkyldiyl” by itself or as part of another substituent refers to a saturated or unsaturated, branched, straight-chain or cyclic divalent hydrocarbon group having the stated number of carbon atoms (i.e., C₁-C₆ means from one to six carbon atoms) derived by the removal of one hydrogen atom from each of two different carbon atoms of a parent alkane, alkene or alkyne, or by the removal of two hydrogen atoms from a single carbon atom of a parent alkane, alkene or alkyne. The two monovalent radical centers or each valency of the divalent radical center can form bonds with the same or different atoms. Typical alkyldiyl groups include, but are not limited to, methandiyl; ethyldiyls such as ethan-1,1-diyl, ethan-1,2-diyl, ethen-1,1-diyl, ethen-1,2-diyl; propyldiyls such as propan-1,1-diyl, propan-1,2-diyl, propan-2,2-diyl, propan-1,3-diyl, cyclopropan-1,1-diyl, cyclopropan-1,2-diyl, prop-1-en-1,1-diyl, prop-1-en-1,2-diyl, prop-2-en-1,2-diyl, prop-1-en-1,3-diyl, cycloprop-1-en-1,2-diyl, cycloprop-2-en-1,2-diyl, cycloprop-2-en-1,1-diyl, prop-1-yn-1,3-diyl, etc.; butyldiyls such as, butan-1,1-diyl, butan-1,2-diyl, butan-1,3-diyl, butan-1,4-diyl, butan-2,2-diyl, 2-methyl-propan-1,1-diyl, 2-methyl-propan-1,2-diyl, cyclobutan-1,1-diyl; cyclobutan-1,2-diyl, cyclobutan-1,3-diyl, but-1-en-1,1-diyl, but-1-en-1,2-diyl, but-1-en-1,3-diyl, but-1-en-1,4-diyl, 2-methyl-prop-1-en-1,1-diyl, 2-methanylidene-propan-1,1-diyl, buta-1,3-dien-1,1-diyl, buta-1,3-dien-1,2-diyl, buta-1,3-dien-1,3-diyl, buta-1,3-dien-1,4-diyl, cyclobut-1-en-1,2-diyl, cyclobut-1-en-1,3-diyl, cyclobut-2-en-1,2-diyl, cyclobuta-1,3-dien-1,2-diyl, cyclobuta-1,3-dien-1,3-diyl, but-1-yn-1,3-diyl, but-1-yn-1,4-diyl, buta-1,3-diyn-1,4-diyl, etc.; and the like. Where specific levels of saturation are intended, the nomenclature alkanyldiyl, alkenyldiyl and/or alkynyldiyl is used. Where it is specifically intended that the two valencies are on the same carbon atom, the nomenclature “alkylidene” is used. In some embodiments, the alkyldiyl groups are (C₁-C₁₀) alkyldiyl. In other embodiments, the alkyldiyl groups are (C₁-C₆) alkyldiyl. Also preferred are saturated acyclic alkanyldiyl groups in which the radical centers are at the terminal carbons, e.g., methandiyl (methano); ethan-1,2-diyl (ethano); propan-1,3-diyl (propano); butan-1,4-diyl (butano); and the like (also referred to as alkylenos, defined infra).

“Alkyleno” by itself or as part of another substituent refers to a straight-chain saturated or unsaturated alkyldiyl group having two terminal monovalent radical centers derived by the removal of one hydrogen atom from each of the two terminal carbon atoms of straight-chain parent alkane, alkene or alkyne. The locant of a double bond or triple bond, if present, in a particular alkyleno is indicated in square brackets. Typical alkyleno groups include, but are not limited to, methano; ethylenos such as ethano, etheno, ethyno; propylenos such as propano, prop[1]eno, propa[1,2]dieno, prop[1]yno, etc.; butylenos such as butano, but[1]eno, but[2]eno, buta[1,3]dieno, but[1]yno, but[2]yno, buta[1,3]diyno, etc.; and the like. Where specific levels of saturation are intended, the nomenclature alkano, alkeno and/or alkyno is used. In some embodiments, the alkyleno group is (C₁-C₁₀) alkyleno. In other embodiments, the alkyleno group is (C₁-C₆) alkyleno. In still other embodiments, the alkyleno group is (C₁-C₃) alkyleno. Also preferred are straight-chain saturated alkano groups, e.g., methano, ethano, propano, butano, and the like.

“Heteroalkyl,” Heteroalkanyl,” Heteroalkenyl,” Heteroalkynyl,” Heteroalkyldiyl” and “Heteroalkyleno” by themselves or as part of another substituent refer to alkyl, alkanyl, alkenyl, alkynyl, alkyldiyl and alkyleno groups, respectively, in which one or more of the carbon atoms are each independently replaced with the same or different heteroatoms or heteroatomic groups. Typical heteroatoms and/or heteroatomic groups which can replace the carbon atoms include, but are not limited to, —O—, —S—, —S—O—, —NR′—, —PH—, —S(O)—, —S(O)₂—, —S(O)NR′—, —S(O)₂NR′—, and the like, including combinations thereof, where each R′ is independently hydrogen or (C₁-C₆) alkyl.

“Cycloalkyl” and “Heterocycloalkyl” by themselves or as part of another substituent refer to cyclic versions of “alkyl” and “heteroalkyl” groups, respectively. For heteroalkyl groups, a heteroatom can occupy the position that is attached to the remainder of the molecule. Typical cycloalkyl groups include, but are not limited to, cyclopropyl; cyclobutyls such as cyclobutanyl and cyclobutenyl; cyclopentyls such as cyclopentanyl and cyclopentenyl; cyclohexyls such as cyclohexanyl and cyclohexenyl; and the like. Typical heterocycloalkyl groups include, but are not limited to, tetrahydrofuranyl (e.g., tetrahydrofuran-2-yl, tetrahydrofuran-3-yl, etc.), piperidinyl (e.g., piperidin-1-yl, piperidin-2-yl, etc.), morpholinyl (e.g., morpholin-3-yl, morpholin-4-yl, etc.), piperazinyl (e.g., piperazin-1-yl, piperazin-2-yl, etc.), and the like.

“Acyclic Heteroatomic Bridge” refers to a divalent bridge in which the backbone atoms are exclusively heteroatoms and/or heteroatomic groups. Typical acyclic heteroatomic bridges include, but are not limited to, —O—, —S—, —S—O—, —NR′—, —PH—, —S(O)—, —S(O)₂—, —S(O)NR′—, —S(O)₂NR′—, and the like, including combinations thereof, where each R′ is independently hydrogen or (C₁-C₆) alkyl.

“Parent Aromatic Ring System” refers to an unsaturated cyclic or polycyclic ring system having a conjugated π electron system. Specifically included within the definition of “parent aromatic ring system” are fused ring systems in which one or more of the rings are aromatic and one or more of the rings are saturated or unsaturated, such as, for example, fluorene, indane, indene, phenalene, tetrahydronaphthalene, etc. Typical parent aromatic ring systems include, but are not limited to, aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene, rubicene, tetrahydronaphthalene, triphenylene, trinaphthalene, and the like, as well as the various hydro isomers thereof.

“Aryl” by itself or as part of another substituent refers to a monovalent aromatic hydrocarbon group having the stated number of carbon atoms (i.e., C₅-C₁₅ means from 5 to 15 carbon atoms) derived by the removal of one hydrogen atom from a single carbon atom of a parent aromatic ring system. Typical aryl groups include, but are not limited to, groups derived from aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, as-indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene, rubicene, triphenylene, trinaphthalene, and the like, as well as the various hydro isomers thereof. In some embodiments, the aryl group is (C₅-C₁₅) aryl, with (C₅-C₁₀) being even more preferred. Preferred aryls are cyclopentadienyl, phenyl and naphthyl.

“Arylaryl” by itself or as part of another substituent refers to a monovalent hydrocarbon group derived by the removal of one hydrogen atom from a single carbon atom of a ring system in which two or more identical or non-identical parent aromatic ring systems are joined directly together by a single bond, where the number of such direct ring junctions is one less than the number of parent aromatic ring systems involved. Typical arylaryl groups include, but are not limited to, biphenyl, triphenyl, phenyl-naphthyl, binaphthyl, biphenyl-naphthyl, and the like. Where the number of carbon atoms in an arylaryl group are specified, the numbers refer to the carbon atoms comprising each parent aromatic ring. For example, (C₅-C₁₅) arylaryl is an arylaryl group in which each aromatic ring comprises from 5 to 15 carbons, e.g., biphenyl, triphenyl, binaphthyl, phenylnaphthyl, etc. Preferably, each parent aromatic ring system of an arylaryl group is independently a (C₅-C₁₅) aromatic, more preferably a (C₅-C₁₀) aromatic. Also preferred are arylaryl groups in which all of the parent aromatic ring systems are identical, e.g., biphenyl, triphenyl, binaphthyl, trinaphthyl, etc.

“Biaryl” by itself or as part of another substituent refers to an arylaryl group having two identical parent aromatic systems joined directly together by a single bond. Typical biaryl groups include, but are not limited to, biphenyl, binaphthyl, bianthracyl, and the like. Preferably, the aromatic ring systems are (C₅-C₁₅) aromatic rings, more preferably (C₅-C₁₀) aromatic rings. A particularly preferred biaryl group is biphenyl.

“Arylalkyl” by itself or as part of another substituent refers to an acyclic alkyl group in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp³ carbon atom, is replaced with an aryl group. Typical arylalkyl groups include, but are not limited to, benzyl, 2-phenylethan-1-yl, 2-phenylethen-1-yl, naphthylmethyl, 2-naphthylethan-1-yl, 2-naphthylethen-1-yl, naphthobenzyl, 2-naphthophenylethan-1-yl and the like. Where specific alkyl moieties are intended, the nomenclature arylalkanyl, arylalkenyl and/or arylalkynyl is used. In preferred embodiments, the arylalkyl group is (C₆-C₂₁) arylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of the arylalkyl group is (C₁-C₆) and the aryl moiety is (C₅-C₁₅). In some embodiments the arylalkyl group is (C₆-C₁₃), e.g., the alkanyl, alkenyl or alkynyl moiety of the arylalkyl group is (C₁-C₃) and the aryl moiety is (C₅-C₁₀).

“Parent Heteroaromatic Ring System” refers to a parent aromatic ring system in which one or more carbon atoms are each independently replaced with the same or different heteroatoms or heteroatomic groups. Typical heteroatoms or heteroatomic groups to replace the carbon atoms include, but are not limited to, N, NH, P, O, S, S(O), S(O)₂, Si, etc. Specifically included within the definition of “parent heteroaromatic ring systems” are fused ring systems in which one or more of the rings are aromatic and one or more of the rings are saturated or unsaturated, such as, for example, benzodioxan, benzofuran, chromane, chromene, indole, indoline, xanthene, etc. Also included in the definition of “parent heteroaromatic ring system” are those recognized rings that include common substituents, such as, for example, benzopyrone and 1-methyl-1,2,3,4-tetrazole. Specifically excluded from the definition of “parent heteroaromatic ring system” are benzene rings fused to cyclic polyalkylene glycols such as cyclic polyethylene glycols. Typical parent heteroaromatic ring systems include, but are not limited to, acridine, benzimidazole, benzisoxazole, benzodioxan, benzodioxole, benzofuran, benzopyrone, benzothiadiazole, benzothiazole, benzotriazole, benzoxaxine, benzoxazole, benzoxazoline, carbazole, β-carboline, chromane, chromene, cinnoline, furan, imidazole, indazole, indole, indoline, indolizine, isobenzofuran, isochromene, isoindole, isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline, phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline, quinoline, quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole, thiophene, triazole, xanthene, and the like.

“Heteroaryl” by itself or as part of another substituent refers to a monovalent heteroaromatic group having the stated number of ring atoms (e.g., “5-14 membered” means from 5 to 14 ring atoms) derived by the removal of one hydrogen atom from a single atom of a parent heteroaromatic ring system. Typical heteroaryl groups include, but are not limited to, groups derived from acridine, benzimidazole, benzisoxazole, benzodioxan, benzodiaxole, benzofuran, benzopyrone, benzothiadiazole, benzothiazole, benzotriazole, benzoxazine, benzoxazole, benzoxazoline, carbazole, β-carboline, chromane, chromene, cinnoline, furan, imidazole, indazole, indole, indoline, indolizine, isobenzofuran, isochromene, isoindole, isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline, phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline, quinoline, quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole, thiophene, triazole, xanthene, and the like, as well as the various hydro isomers thereof. In some embodiments, the heteroaryl group is a 5-14 membered heteroaryl, with 5-10 membered heteroaryl being particularly preferred.

“Heteroaryl-Heteroaryl” by itself or as part of another substituent refers to a monovalent heteroaromatic group derived by the removal of one hydrogen atom from a single atom of a ring system in which two or more identical or non-identical parent heteroaromatic ring systems are joined directly together by a single bond, where the number of such direct ring junctions is one less than the number of parent heteroaromatic ring systems involved. Typical heteroaryl-heteroaryl groups include, but are not limited to, bipyridyl, tripyridyl, pyridylpurinyl, bipurinyl, etc. Where the number of atoms are specified, the numbers refer to the number of atoms comprising each parent heteroaromatic ring systems. For example, 5-15 membered heteroaryl-heteroaryl is a heteroaryl-heteroaryl group in which each parent heteroaromatic ring system comprises from 5 to 15 atoms, e.g., bipyridyl, tripuridyl, etc. Preferably, each parent heteroaromatic ring system is independently a 5-15 membered heteroaromatic, more preferably a 5-10 membered heteroaromatic. Also preferred are heteroaryl-heteroaryl groups in which all of the parent heteroaromatic ring systems are identical.

“Biheteroaryl” by itself or as part of another substituent refers to a heteroaryl-heteroaryl group having two identical parent heteroaromatic ring systems joined directly together by a single bond. Typical biheteroaryl groups include, but are not limited to, bipyridyl, bipurinyl, biquinolinyl, and the like. Preferably, the heteroaromatic ring systems are 5-15 membered heteroaromatic rings, more preferably 5-10 membered heteroaromatic rings.

“Heteroarylalkyl” by itself or as part of another substituent refers to an acyclic alkyl group in which one of the hydrogen atoms bonded to a carbon atom, typically a terminal or sp³ carbon atom, is replaced with a heteroaryl group. Where specific alkyl moieties are intended, the nomenclature heteroarylalkanyl, heteroarylalkenyl and/or heteroarylalkynyl is used. In preferred embodiments, the heteroarylalkyl group is a 6-21 membered heteroarylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety of the heteroarylalkyl is (C₁-C₆) alkyl and the heteroaryl moiety is a 5-15-membered heteroaryl. In particularly preferred embodiments, the heteroarylalkyl is a 6-13 membered heteroarylalkyl, e.g., the alkanyl, alkenyl or alkynyl moiety is (C₁-C₃) alkyl and the heteroaryl moiety is a 5-10 membered heteroaryl.

“Halogen” or “Halo” by themselves or as part of another substituent, unless otherwise stated, refer to fluoro, chloro, bromo and iodo.

“Haloalkyl” by itself or as part of another substituent refers to an alkyl group in which one or more of the hydrogen atoms is replaced with a halogen. Thus, the term “haloalkyl” is meant to include monohaloalkyls, dihaloalkyls, trihaloalkyls, etc. up to perhaloalkyls. For example, the expression “(C₁-C₂) haloalkyl” includes fluoromethyl, difluoromethyl, trifluoromethyl, 1-fluoroethyl, 1,1-difluoroethyl, 1,2-difluoroethyl, 1,1,1-trifluoroethyl, perfluoroethyl, etc.

The above-defined groups may include prefixes and/or suffixes that are commonly used in the art to create additional well-recognized substituent groups. As examples, “alkyloxy” or “alkoxy” refers to a group of the formula —OR″, “alkylamine” refers to a group of the formula —NHR″ and “dialkylamine” refers to a group of the formula —NR″R″, where each R″ is independently an alkyl. As another example, “haloalkoxy” or “haloalkyloxy” refers to a group of the formula —OR′″, where R′″ is a haloalkyl.

“Protecting group” refers to a group of atoms that, when attached to a reactive functional group in a molecule, mask, reduce or prevent the reactivity of the functional group. Typically, a protecting group may be selectively removed as desired during the course of a synthesis. Examples of protecting groups can be found in Greene and Wuts, Protective Groups in Organic Chemistry, 3^(rd) Ed., 1999, John Wiley & Sons, NY and Harrison et al., Compendium of Synthetic Organic Methods, Vols. 1-8, 1971-1996, John Wiley & Sons, NY. Representative amino protecting groups include, but are not limited to, formyl, acetyl, trifluoroacetyl, benzyl, benzyloxycarbonyl (“CBZ”), tert-butoxycarbonyl (“Boc”), trimethylsilyl (“TMS”), 2-trimethylsilyl-ethanesulfonyl (“TES”), trityl and substituted trityl groups, allyloxycarbonyl, 9-fluorenylmethyloxycarbonyl (“FMOC”), nitro-veratryloxycarbonyl (“NVOC”) and the like. Representative hydroxyl protecting groups include, but are not limited to, those where the hydroxyl group is either acylated or alkylated such as benzyl and trityl ethers, as well as alkyl ethers, tetrahydropyranyl ethers, trialkylsilyl ethers (e.g., TMS or TIPPS groups) and allyl ethers.

“Prodrug” refers to a derivative of an active spiro 2,4-pyrimidinediamine compound (drug) that requires a transformation under the conditions of use, such as within the body, to release the active spiro 2,4-pyrimidinediamine drug. Prodrugs are frequently, but not necessarily, pharmacologically inactive until converted into the active drug. Prodrugs are typically obtained by masking a functional group in the spiro 2,4-pyrimidinediamine drug believed to be in part required for activity with a progroup (defined below) to form a promoiety which undergoes a transformation, such as cleavage, under the specified conditions of use to release the functional group, and hence the active spiro 2,4-pyrimidinediamine drug. The cleavage of the promoiety may proceed spontaneously, such as by way of a hydrolysis reaction, or it may be catalyzed or induced by another agent, such as by an enzyme, by light, by acid or base, or by a change of or exposure to a physical or environmental parameter, such as a change of temperature. The agent may be endogenous to the conditions of use, such as an enzyme present in the cells to which the prodrug is administered or the acidic conditions of the stomach, or it may be supplied exogenously.

A wide variety of progroups, as well as the resultant promoieties, suitable for masking functional groups in the active 2,4-pyrimidinediamines compounds to yield prodrugs are well-known in the art. For example, a hydroxyl functional group may be masked as a sulfonate, ester or carbonate promoiety, which may be hydrolyzed in vivo to provide the hydroxyl group. An amino functional group may be masked as an amide, carbamate, imine, urea, phosphenyl, phosphoryl or sulfenyl promoiety, which may be hydrolyzed in vivo to provide the amino group. A carboxyl group may be masked as an ester (including silyl esters and thioesters), amide or hydrazide promoiety, which may be hydrolyzed in vivo to provide the carboxyl group. Nitrogen protecting groups and nitrogen pro-drugs of the invention may include lower alkyl groups as well as amides, carbamates, etc. Other specific examples of suitable progroups and their respective promoieties will be apparent to those of skill in the art.

“Progroup” refers to a type of protecting group that, when used to mask a functional group within an active spiro 2,4-pyrimidinediamine drug to form a promoiety, converts the drug into a prodrug. Progroups are typically attached to the functional group of the drug via bonds that are cleavable under specified conditions of use. Thus, a progroup is that portion of a promoiety that cleaves to release the functional group under the specified conditions of use. As a specific example, an amide promoiety of the formula —NH—C(O)CH₃ comprises the progroup —C(O)CH₃.

“Fc Receptor” refers to a member of the family of cell surface molecules that binds the Fc portion (containing the specific constant region) of an immunoglobulin. Each Fc receptor binds immunoglobulins of a specific type. For example the Fcα receptor (“FcαR”) binds IgA, the FcεR binds IgE and the FcγR binds IgG.

The FcαR family includes the polymeric Ig receptor involved in epithelial transport of IgA/IgM, the mycloid specific receptor RcαRI (also called CD89), the Fcα/μR and at least two alternative IgA receptors (for a recent review see Monteiro & van de Winkel, 2003, Annu. Rev. Immunol, advanced e-publication. The FcαRI is expressed on neutrophils, eosinophils, monocytes/macrophages, dendritic cells and kupfer cells. The FcαRI includes one alpha chain and the FcR gamma homodimer that bears an activation motif (ITAM) in the cytoplasmic domain and phosphorylates Syk kinase.

The FcεR family includes two types, designated FcεRI and FcεRII (also known as CD23). FcεRI is a high affinity receptor (binds IgE with an affinity of about 10¹⁰M⁻¹) found on mast, basophil and eosinophil cells that anchors monomeric IgE to the cell surface. The FcεRI possesses one alpha chain, one beta chain and the gamma chain homodimer discussed above. The FcεRII is a low affinity receptor expressed on mononuclear phagocytes, B lymphocytes, eosinophils and platelets. The FcεRII comprises a single polypeptide chain and does not include the gamma chain homodimer.

The FcγR family includes three types, designated FcγRI (also known as CD64), FcγRII (also known as CD32) and FcγRIII (also known as CD16). FcγRI is a high affinity receptor (binds IgG1 with an affinity of 10⁸M⁻¹) found on mast, basophil, mononuclear, neutrophil, eosinophil, dendritic and phagocyte cells that anchors monomeric IgG to the cell surface. The FcγRI includes one alpha chain and the gamma chain dimer shared by FcαRI and FcεRI.

The FcγRII is a low affinity receptor expressed on neutrophils, monocytes, eosinophils, platelets and B lymphocytes. The FcγRII includes one alpha chain, and does not include the gamma chain homodimer discussed above.

The FcγRIII is a low affinity (binds IgG1 with an affinity of 5×10⁵M⁻¹) expressed on NK, eosinophil, macrophage, neutrophil and mast cells. It comprises one alpha chain and the gamma homodimer shared by FcαRI, FcεRI and FcγRI.

Skilled artisans will recognize that the subunit structure and binding properties of these various Fc receptors, cell types expressing them, are not completely characterized. The above discussion merely reflects the current state-of-the-art regarding these receptors (see, e.g., Immunobiology: The Immune System in Health & Disease, 5^(th) Edition, Janeway et al., Eds, 2001, ISBN 0-8153-3642-x, FIG. 9.30 at pp. 371), and is not intended to be limiting with respect to the myriad receptor signaling cascades that can be regulated with the compounds described herein.

“Fc Receptor-Mediated Degranulation” or “Fc Receptor-Induced Degranulation” refers to degranulation that proceeds via an Fc receptor signal transduction cascade initiated by crosslinking of an Fc receptor.

“IgE-Induced Degranulation” or “FcεRI-Mediated Degranulation” refers to degranulation that proceeds via the IgE receptor signal transduction cascade initiated by crosslinking of FcεR1-bound IgE. The crosslinking may be induced by an IgE-specific allergen or other multivalent binding agent, such as an anti-IgE antibody. Referring to FIG. 2, in mast and/or basophil cells, the FcεRI signaling cascade leading to degranulation may be broken into two stages: upstream and downstream. The upstream stage includes all of the processes that occur prior to calcium ion mobilization (illustrated as “Ca²⁺ ” in FIG. 2; see also FIG. 3). The downstream stage includes calcium ion mobilization and all processes downstream thereof. Compounds that inhibit FcεRI-mediated degranulation may act at any point along the FcεRI-mediated signal transduction cascade. Compounds that selectively inhibit upstream FcεRI-mediated degranulation act to inhibit that portion of the FcεRI signaling cascade upstream of the point at which calcium ion mobilization is induced. In cell-based assays, compounds that selectively inhibit upstream FcεRI-mediated degranulation inhibit degranulation of cells such as mast or basophil cells that are activated or stimulated with an IgE-specific allergen or binding agent (such as an anti-IgE antibody) but do not appreciably inhibit degranulation of cells that are activated or stimulated with degranulating agents that bypass the FcεRI signaling pathway, such as, for example the calcium ionophores ionomycin and A23187.

“IgG-Induced Degranulation” or “FcγRI-Mediated Degranulation” refers to degranulation that proceeds via the FcγRI signal transduction cascade initiated by crosslinking of FcγRI-bound IgG. The crosslinking may be induced by an IgG-specific allergen or another multivalent binding agent, such as an anti-IgG or fragment antibody. Like the FcεRI signaling cascade, in mast and basophil cells the FcγRI signaling cascade also leads to degranulation which may be broken into the same two stages: upstream and downstream. Similar to FcεRI-mediated degranulation, compounds that selectively inhibit upstream FcγRI-mediated degranulation act upstream of the point at which calcium ion mobilization is induced. In cell-based assays, compounds that selectively inhibit upstream FcγRI-mediated degranulation inhibit degranulation of cells such as mast or basophil cells that are activated or stimulated with an IgG-specific allergen or binding agent (such as an anti-IgG antibody or fragment) but do not appreciably inhibit degranulation of cells that are activated or stimulated with degranulating agents that bypass the FcγRI signaling pathway, such as, for example the calcium ionophores ionomycin and A23187.

“Ionophore-Induced Degranulation” or “Ionophore-Mediated Degranulation” refers to degranulation of a cell, such as a mast or basophil cell, that occurs upon exposure to a calcium ionophore such as, for example, ionomycin or A23187.

“Syk Kinases” refers to the well-known 72 kDa non-receptor (cytoplasmic) spleen protein tyrosine kinase expressed in B-cells and other hematopoetic cells. Syk kinase includes two consensus Src-homology 2 (SH2) domains in tandem that bind to phosphorylated immunoreceptor tyrosine-based activation motifs (“ITAMs”), a “linker” domain and a catalytic domain (for a review of the structure and function of Syk kinase see Sada et al., 2001, J. Biochem. (Tokyo) 130:177-186); see also Turner et al., 2000, Immunology Today 21:148-154). Syk kinase has been extensively studied as an effector of B-cell receptor (BCR) signaling (Turner et al., 2000, supra). Syk kinase is also critical for tyrosine phosphorylation of multiple proteins which regulate important pathways leading from immunoreceptors, such as Ca²⁺ mobilization and mitogen-activated protein kinase (MAPK) cascades (see, e.g., FIG. 2) and degranulation. Syk kinase also plays a critical role in integrin signaling in neutrophils (see, e.g., Mocsai et al., 2002, Immunity 16:547-558).

As used herein, Syk kinase includes kinases from any species of animal, including but not limited to, homosapiens, simian, bovine, porcine, rodent, etc., recognized as belonging to the Syk family. Specifically included are isoforms, splice variants, allelic variants, mutants, both naturally occurring and man-made. The amino acid sequences of such Syk kinases are well known and available from GENBANK. Specific examples of mRNAs encoding different isoforms of human Syk kinase can be found at GENBANK accession no. gi|21361552|ref|NM_(—)003177.2|, gi|496899|emb|Z29630.1|HSSYKPTK[496899] and gi|15030258|gb|BC011399.1|BC0111399[15030258], which are incorporated herein by reference.

Skilled artisans will appreciate that tyrosine kinases belonging to other families may have active sites or binding pockets that are similar in three-dimensional structure to that of Syk. As a consequence of this structural similarity, such kinases, referred to herein as “Syk mimics,” are expected to catalyze phosphorylation of substrates phosphorylated by Syk. Thus, it will be appreciated that such Syk mimics, signal transduction cascades in which such Syk mimics play a role and biological responses effected by such Syk mimics and Syk mimic-dependent signaling cascades may be regulated, and in particular inhibited, with the spiro 2,4-pyrimidinediamine compounds described herein.

“Syk-Dependent Signaling Cascade” refers to a signal transduction cascade in which Syk kinase plays a role. Non-limiting examples of such Syk-dependent signaling cascades include the FcαRI, FcεRI, FcγRI, FcγRIII, BCR and integrin signaling cascades.

“Autoimmune Disease” refers to those diseases which are commonly associated with the nonanaphylactic hypersensitivity reactions (Type II, Type III and/or Type IV hypersensitivity reactions) that generally result as a consequence of the subject's own humoral and/or cell-mediated immune response to one or more immunogenic substances of endogenous and/or exogenous origin. Such autoimmune diseases are distinguished from diseases associated with the anaphylactic (Type I or IgE-mediated) hypersensitivity reaction.

6.3 Spiro 2,4-Pyrimidinediamine Compounds

Spiro 2,4-pyrimidinediamine compounds according to structural formula (I) are provided herein:

including salts, hydrates, solvates and N-oxides thereof, wherein:

L¹ is a direct bond or a linker;

L is a direct bond or a linker;

R² is selected from the group consisting of (C1-C6) alkyl optionally substituted with one or more of the same or different R⁸ groups, (C3-C8) alkyl optionally substituted with one or more of the same or different R⁸ groups, 3-8 membered cycloheteroalkyl optionally substituted with one or more of the same or different R⁸ groups, (C5-C15) aryl optionally substituted with one or more of the same or different R⁸ groups, phenyl optionally substituted with one or more of the same or different R⁸ groups and 5-15 membered heteroaryl optionally substituted with one or more of the same or different R⁸ groups;

R⁴ is

each W is, independently of the other, —CR³¹R³¹—;

X is selected from the group consisting of —N— and —CH—;

Y and Z are each, independently of one another, selected from the group consisting of —O—, —S—, —SO—, —SO₂—, —SONR³⁶—, —NH—, —NR³′- and —NR³⁷—;

R⁵ is selected from the group consisting of hydrogen, an electronegative group, —OR^(d), —SR^(d), (C1-C3) haloalkyloxy, (C1-C3) perhaloalkyloxy, —NR^(c)R^(c), halogen, (C1-C3) haloalkyl, (C1-C3) perhaloalkyl, —CF₃, —CH₂CF₃, —CF₂CF₃, —CN, —NC, —OCN, —SCN, —NO, —NO₂, —N₃, —S(O)R^(d), —S(O)₂R^(d), —S(O)₂OR^(d), —S(O)NR^(c)R^(c); —S(O)₂NR^(c)R^(c), —OS(O)R^(d), —OS(O)₂R^(d), —OS(O)₂OR^(d), —OS(O)NR^(c)R^(c), —OS(O)₂NR^(c)R^(c), —C(O)R^(d), —C(O)OR^(d), —C(O)NR^(c)R^(c), —C(NH)NR^(c)R^(c), —OC(O)R^(d), —SC(O)R^(d), —OC(O)OR^(d), —SC(O)OR^(d), —OC(O)NR^(c)R^(c), —SC(O)NR^(c)R^(c), —OC(NH)NR^(c)R^(c), —SC(NH)NR^(c)R^(c), —[NHC(O)]_(n)R^(d), —[NHC(O)]_(n)OR^(d), —[NHC(O)]_(n)NR^(c)R^(c) and —[NHC(NH)]_(n)NR^(c)R^(c), (C5-C10) aryl optionally substituted with one or more of the same or different R⁸ groups, phenyl optionally substituted with one or more of the same or different R⁸ groups, (C6-C16) arylalkyl optionally substituted with one or more of the same or different R⁸ groups, 5-10 membered heteroaryl optionally substituted with one or more of the same or different R⁸ groups and 6-16 membered heteroarylalkyl optionally substituted with one or more of the same or different R⁸ groups, (C1-C6) alkyl optionally substituted with one or more of the same or different R⁸ groups, (C1-C4) alkanyl optionally substituted with one or more of the same or different R⁸ groups, (C2-C4) alkenyl optionally substituted with one or more of the same or different R⁸ groups and (C2-C4) alkynyl optionally substituted with one or more of the same or different R⁸ groups;

R⁶ independently is selected from the group consisting of hydrogen, an electronegative group, —OR^(d), —SR^(d), (C1-C3) haloalkyloxy, (C1-C3) perhaloalkyloxy, —NR^(c)R^(c), halogen, (C1-C3) haloalkyl, (C1-C3) perhaloalkyl, —CF₃, —CH₂CF₃, —CF₂CF₃, —CN, —NC, —OCN, —SCN, —NO, —NO₂, —N₃, —S(O)R^(d), —S(O)₂R^(d), —S(O)₂OR^(d), —S(O)NR^(c)R^(c); —S(O)₂NR^(c)R^(c), —OS(O)R^(d), —OS(O)₂R^(d), —OS(O)₂OR^(d), —OS(O)NR^(c)R^(c), —OS(O)₂NR^(c)R^(c), —C(O)R^(d), —C(O)OR^(d), —C(O)NR^(c)R^(c), —C(NH)NR^(c)R^(c), —OC(O)R^(d), —SC(O)R^(d), —OC(O)OR^(d), —SC(O)OR^(d), —OC(O)NR^(c)R^(c), —SC(O)NR^(c)R^(c), —OC(NH)NR^(c)R^(c), —SC(NH)NR^(c)R^(c), —[NHC(O)]_(n)R^(d), —[NHC(O)]_(n)OR^(d), —[NHC(O)]_(n)NR^(c)R^(c) and —[NHC(NH)]_(n)NR^(c)R^(c), (C5-C10) aryl optionally substituted with one or more of the same or different R⁸ groups, phenyl optionally substituted with one or more of the same or different R⁸ groups, (C6-C16) arylalkyl optionally substituted with one or more of the same or different R⁸ groups, 5-10 membered heteroaryl optionally substituted with one or more of the same or different R⁸ groups and 6-16 membered heteroarylalkyl optionally substituted with one or more of the same or different R⁸ groups;

R⁸ is selected from the group consisting of R^(a), R^(b), R^(a) substituted with one or more of the same or different R^(a) or R^(b), —OR^(a) substituted with one or more of the same or different R^(a) or R^(b), —B(OR^(a))₂, —B(NR^(c)R^(c))₂, —(CH₂)_(m)—R^(b), —(CHR^(a))_(m)—R^(b), —O—(CH₂)_(m)—R^(b), —S—(CH₂)_(m)—R^(b), —O—CHR^(a)R^(b), —O—CR^(a)(b)₂, —O—(CHR^(a))_(m)R^(b), —O(CH₂)_(m)—CH[(CH₂)_(m)R^(b)]R^(b), —S—(CHR^(a))_(m)—R^(b), —C(O)NH—(CH₂)_(m)—R^(b), —C(O)NH—(CHR^(a))_(m)—R^(b), —O—(CH₂)_(m)—C(O)NH—(CH₂)_(m)—R^(b), —S—(CH₂)_(n)—C(O)NH—(CH₂)_(n)—R^(b), —O—(CHR^(a))_(m)—C(O)NH—(CHR^(a))_(n)—R^(b), —S—(CHR^(a))_(m)—C(O)NH—(CHR^(a))_(m)—R^(b), —NH—(CH₂)_(m)—R^(b), —NH—(CHR^(a))_(m)—R^(b), —NH[(CH₂)_(m)R^(b)], —N[(CH₂)_(m)R^(b)]₂, —NH—C(O)—NH—(CH₂)_(n)—R^(b), —NH—C(O)—(CH₂)_(m)—CHR^(b)R^(b) and —NH—(CH₂)_(n)—C(O)—NH—(CH₂)_(n)—R^(b);

each R³¹ is, independently of the others, hydrogen or (C1-C6) alkyl optionally substituted with one or more of the same or different R⁸ groups;

each R³⁵ is, independently of the other, selected from the group consisting of hydrogen and R⁸, or, alternatively, the two R³⁵ groups are taken together to form an oxo (═O), or ═NR³⁸ group;

each R³⁶ is, independently of the others, selected from the group consisting of hydrogen and (C1-C6) alkyl;

each R³⁷ is, independently of the others, selected from the group consisting of hydrogen and a progroup;

R³⁸ is selected from the group consisting of hydrogen, (C1-C6) alkyl and (C5-C14) aryl;

each R^(a) is, independently of the others, selected from the group consisting of hydrogen, (C1-C6) alkyl, (C3-C8) cycloalkyl, cyclohexyl, (C4-C11) cycloalkylalkyl, (C5-C10) aryl, phenyl, (C6-C16) arylalkyl, benzyl, 2-6 membered heteroalkyl, 3-8 membered cycloheteroalkyl, morpholinyl, piperazinyl, homopiperazinyl, piperidinyl, 4-11 membered cycloheteroalkylalkyl, 5-10 membered heteroaryl and 6-16 membered heteroarylalkyl;

each R^(b) is, independently of the others, a suitable group independently selected from the group consisting of ═O, —OR^(d), (C1-C3) haloalkyloxy, —OCF₃, ═S, —SR^(d), ═NR^(d), ═NOR^(d), —NR^(c)R^(c), halogen, —CF₃, —CN, —NC, —OCN, —SCN, —NO, —NO₂, ═N₂, —N₃, —S(O)R^(d), —S(O)₂R^(d), —S(O)₂OR^(d), —S(O)NR^(c)R^(c), —S(O)₂NR^(c)R^(c), —OS(O)R^(d), —OS(O)₂R^(d), —OS(O)₂OR^(d), —OS(O)₂NR^(c)R^(c), —C(O)R^(d), —C(O)OR^(d), —C(O)NR^(c)R^(c), —C(NH)NR^(c)R^(c), —C(NR^(a))NR^(c)R^(c), —C(NOH)R^(a), —C(NOH)NR^(c)R^(c), —OC(O)R^(d), —OC(O)OR^(d), —OC(O)NR^(c)R^(c), —OC(NH)NR^(c)R^(c), —O—C(NR^(a))NR^(c)R^(c), —[NHC(O)]_(n)R^(d), —[NR^(a)C(O)]_(n)R^(d), —[NHC(O)]_(n)OR^(d), —[NR^(a)C(O)]_(n)OR^(d), [NHC(O)]_(n)NR^(c)R^(c), —[NR^(a)C(O)]_(n)NR^(c)R^(c), —[NHC(NH)]_(n)NR^(c)R^(c) and —[NR^(a)C(NR^(a))]_(n)NR^(c)R^(c);

each R^(c) is, independently or the others, a protecting group or R^(a), or, alternatively, each R^(c) is taken together with the nitrogen atom to which it is bonded to form a 5 to 8-membered cycloheteroalkyl or heteroaryl which may optionally include one or more of the same or different additional heteroatoms and which may optionally be substituted with one or more of the same or different R^(a) or suitable R^(b) groups;

each R^(d) is, independently of the others, a protecting group or R^(a);

each m is, independently of the others, an integer from 1 to 3;

each n is, independently of the others, an integer from 0 to 3; and

o is an integer from 1 to 6.

In compounds of structural formula (I), L¹ and L² represent, independently of one another, a direct bond or a linker. Thus, as will be appreciated by skilled artisans, the substituents R² and/or R⁴ may be bonded either directly to their respective nitrogen atoms or, alternatively, spaced away from their respective nitrogen atoms by way of a linker. The identity of the linker is not critical and typical suitable linkers include, but are not limited to, (C1-C6) alkyldiyls, (C1-C6) alkenos and (C1-C6) heteroalkyldiyls, each of which may be optionally substituted with one or more of the same or different R⁸ groups, where R⁸ is as previously defined for structural formula (I). In some embodiments, L¹ and L² are each, independently of one another, selected from the group consisting of a direct bond, (C1-C3) alkyldiyl optionally substituted with one or more of the same or different R^(a), suitable R^(b) or R⁹ groups and 1-3 membered heteroalkyldiyl optionally substituted with one or more of the same or different R^(a), suitable R^(b) or R⁹ groups, wherein R⁹ is selected from the group consisting of (C1-C3) alkyl, —OR^(a), —C(O)OR^(a), (C5-C10) aryl optionally substituted with one or more of the same or different halogens, phenyl optionally substituted with one or more of the same or different halogens, 5-10 membered heteroaryl optionally substituted with one or more of the same or different halogens and 6 membered heteroaryl optionally substituted with one or more of the same or different halogens; and R^(a) and R^(b) are as previously defined for structural formula (I). Specific R⁹ groups that may be used to substitute L¹ and L² include —OR^(a), —C(O)OR^(a), phenyl, halophenyl and 4-halophenyl, wherein R^(a) is as previously defined for structural formula (I).

In other embodiments, L¹ and L² are each, independently of one another, selected from the group consisting of methano, ethano and propano, each of which may be optionally monosubstituted with an R⁹ group, where R⁹ is as previously defined above.

In the above embodiments, specific R^(a) groups that may be included in R⁹ groups are selected from the group consisting of hydrogen, (C₁-C₆) alkyl, phenyl and benzyl.

In still other embodiments, L¹ and L² are each a direct bond such that the spiro 2,4-pyrimidinediamine compounds are described by structural formula (V):

including salts, hydrates, solvates and N-oxides thereof, wherein R², R⁴, R⁵ and R⁶ are as previously defined for structural formula (I). Other embodiments of the spiro 2,4-pyrimidinediamine compounds of structural Formulae (I) and (V) are described below.

In some embodiments of compounds of structural Formulae (I) and (V), R⁵ is halo, fluoro or —CF₃. In other embodiments, R⁵ is fluoro.

In some embodiments of compounds of structural Formulae (I) and (V), R⁶ is hydrogen. In other embodiments, Y and Z are independently selected from the group consisting of —O— and —NH—. In some other embodiments, X is —CH—. In still other embodiments, Y is —O— and Z is —NH—.

In some embodiments of compounds of structural Formulae (I) and (V), each R³⁵ is hydrogen. In other embodiments, the two R³⁵ groups form an oxo group.

In some embodiments of compounds of structural Formulae (I) and (V), o is an integer from 1 to 4. In other embodiments, o is 1.

In some embodiments of structural Formulae (I) and (V), each R³¹ is independently hydrogen or (C₁-C₆) alkyl. In other embodiments, each R³¹ is hydrogen.

In some embodiments of structural Formulae (I) and (V), R² is phenyl optionally substituted with one or more of the same or different R⁸ groups. In other embodiments, R² is a disubstituted phenyl group with two R^(b) groups or R² is a trisubstituted phenyl group with three R^(b) groups. In still other embodiments, R² is

In some embodiments of structural Formulae (I) and (V), R⁵ is halo, fluoro or —CF³ and R⁶ is hydrogen. In other embodiments, R⁵ is fluoro and R⁶ is hydrogen. In still other embodiments, the two R³⁵ groups form an oxo group, Y is O, Z is NH, X is CH and each R³¹ is hydrogen. In still other embodiments, R⁵ is fluoro and R⁶ is hydrogen.

In some embodiments of structural Formulae (I) and (V), R² is phenyl optionally substituted with one or more of the same or different R⁸ groups. In other embodiments, R² is a disubstituted phenyl group with two R^(b) groups or R² is a trisubstituted phenyl group with three R^(b) groups. In still other embodiments, R² is

In still other embodiments, o is 1. In still other embodiments, R2 is phenyl optionally substituted with one or more of the same or different R8 groups. In still other embodiments, R2 is a disubstituted phenyl group with two R^(b) groups or R2 is a trisubstituted phenyl group with three R^(b) groups. In still other embodiments, R² is

Also specifically described are combinations of the above embodiments.

Those of skill in the art will appreciate that the spiro 2,4-pyrimidinediamine compounds described herein may include functional groups that can be masked with progroups to create prodrugs. Such prodrugs are usually, but need not be, pharmacologically inactive until converted into their active drug form. For example, ester groups commonly undergo acid-catalyzed hydrolysis to yield the parent carboxylic acid when exposed to the acidic conditions of the stomach, or base-catalyzed hydrolysis when exposed to the basic conditions of the intestine or blood. Thus, when administered to a subject orally, 2,4-pyrimidinediamines that include ester moieties may be considered prodrugs of their corresponding carboxylic acid, regardless of whether the ester form is pharmacologically active.

In the prodrugs described herein, any available functional moiety may be masked with a progroup to yield a prodrug. Functional groups within the spiro 2,4-pyrimidinediamine compounds that may be masked with progroups for inclusion in a promoiety include, but are not limited to, amines (primary and secondary), hydroxyls, sulfanyls (thiols), carboxyls, etc. Myriad progroups suitable for masking such functional groups to yield promoieties that are cleavable under the desired conditions of use are known in the art. All of these progroups, alone or in combinations, may be included in the prodrugs described herein.

In some, embodiments, the prodrugs are compounds according to structural formula (I) in which R^(c) and R^(d) may be, in addition to their previously-defined alternatives, a progroup.

Those of skill in the art will appreciate that many of the compounds and prodrugs described herein, as well as the various compound species specifically described and/or illustrated herein, may exhibit the phenomena of tautomerism, conformational isomerism, geometric isomerism and/or optical isomerism. For example, the compounds and prodrugs described herein may include one or more chiral centers and/or double bonds and as a consequence may exist as stereoisomers, such as double-bond isomers (i.e., geometric isomers), enantiomers and diastereomers and mixtures thereof, such as racemic mixtures. As another example, the compounds and prodrugs described herein may exist in several tautomeric forms, including, for example, the enol form, the keto form and mixtures thereof. As the various compound names, formulae and compound drawings within the specification and claims can represent only one of the possible tautomers, conformational isomers, optical isomers or geometric isomers, it should be understood that the compounds or prodrugs described herein include all possible tautomers, conformational isomers, optical isomers and/or geometric isomers, as well as mixtures of these various different isomers. In cases of limited rotation around the 2,4-pyrimidinediamine core structure, atropisomers are also possible and are also specifically included in the compounds described herein.

Moreover, skilled artisans will appreciate that when lists of alternative substituents include members which, owing to valency requirements or other reasons, cannot be used to substitute a particular group, the list is intended to be read in context to include those members of the list that are suitable for substituting the particular group. For example, skilled artisans will appreciate that while all of the listed alternatives for R^(b) can be used to substitute an alkyl group, certain of the alternatives, such as ═O, cannot be used to substitute a phenyl group. It is to be understood that only possible combinations of substituent-group pairs are intended.

The compounds and/or prodrugs described herein may be identified by either their chemical structure or their chemical name. When the chemical structure and the chemical name conflict, the chemical structure is determinative of the identity of the specific compound.

Depending upon the nature of the various substituents, the spiro 2,4-pyrimidinediamine compounds and prodrugs described herein may be in the form of salts. Such salts include salts suitable for pharmaceutical uses (“pharmaceutically-acceptable salts”), salts suitable for veterinary uses, etc. Such salts may be derived from acids or bases, as is well-known in the art.

In some embodiments, the salt is a pharmaceutically acceptable salt. Generally, pharmaceutically acceptable salts are those salts that retain substantially one or more of the desired pharmacological activities of the parent compound and which are suitable for administration to humans. Pharmaceutically acceptable salts include acid addition salts formed with inorganic acids or organic acids. Inorganic acids suitable for forming pharmaceutically acceptable acid addition salts include, by way of example and not limitation, hydrohalide acids (e.g., hydrochloric acid, hydrobromic acid, hydriodic, etc.), sulfuric acid, nitric acid, phosphoric acid, and the like. Organic acids suitable for forming pharmaceutically acceptable acid addition salts include, by way of example and not limitation, acetic acid, trifluoroacetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, oxalic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, palmitic acid, benzoic acid, 3-(4-hydroxybenzoyl) benzoic acid, cinnamic acid, mandelic acid, alkylsulfonic acids (e.g., methanesulfonic acid, ethanesulfonic acid, 1,2-ethane-disulfonic acid, 2-hydroxyethanesulfonic acid, etc.), arylsulfonic acids (e.g., benzenesulfonic acid, 4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid, 4-toluenesulfonic acid, cycloalkylsulfonic acids (e.g., camphorsulfonic acid), 4-methylbicyclo[2.2.2]-oct-2-ene-1-carboxylic acid, glucoheptonic acid, 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid, and the like.

Pharmaceutically acceptable salts also include salts formed when an acidic proton present in the parent compound is either replaced by a metal ion (e.g., an alkali metal ion, an alkaline earth metal ion or an aluminum ion), an ammonium ion or coordinates with an organic base (e.g., ethanolamine, diethanolamine, triethanolamine, N-methylglucamine, morpholine, piperidine, dimethylamine, diethylamine, etc.).

The spiro 2,4-pyrimidinediamine compounds described herein as well as the salts thereof, may also be in the form of hydrates, solvates and N-oxides, as are well-known in the art.

6.4 Methods of Synthesis

The compounds and prodrugs described may be synthesized via a variety of different synthetic routes using commercially available starting materials and/or starting materials prepared by conventional synthetic methods. Suitable exemplary methods that may be routinely adapted to synthesize 2,4-pyrimidinediamine compounds and prodrugs described herein are found in U.S. Pat. No. 5,958,935, U.S. patent application Ser. No. 10/355,543, filed Jan. 31, 2003 (U.S. Publication No. US20040029902-A1), International Publication No. WO 03/063794, U.S. patent application Ser. No. 10/631,029, filed Jul. 29, 2003 and International Publication No. WO 2004/014382, published Feb. 19, 2004.

A variety of exemplary synthetic routes that can be used to synthesize spiro 2,4-pyrimidinediamine compounds are described in Schemes (I)-(VIII), below. In Schemes (I)-(VIII), like-numbered compounds have similar structures. These methods may be routinely adapted to synthesize the prodrugs according to structural formula (II).

In one exemplary embodiment, the compounds can be synthesized from substituted or unsubstituted uracils or thiouracils as illustrated in Scheme (I), below:

In Scheme (I), R², R⁴, R⁵, R⁶, L¹ and L² are as previously defined for structural formula (I), X is a halogen (e.g., F, Cl, Br or I) and Y and Y′ are each, independently of one another, selected from the group consisting of O and S. Referring to Scheme (I), uracil or thiouracil 2 is dihalogenated at the 2- and 4-positions using standard halogenating agent POX₃ (or other standard halogenating agent) under standard conditions to yield 2,4-bishalo pyrimidine 4. Depending upon the R⁵ substituent, in pyrimidine 4, the halide at the C4 position is more reactive towards nucleophiles than the halide at the C2 position. This differential reactivity can be exploited to synthesize 2,4-pyrimidinediamines according to structural formula (I) by first reacting 2,4-bishalopyrimidine 4 with one equivalent of amine 10, yielding 4N-substituted-2-halo-4-pyrimidineamine 8, followed by amine 6 to yield a 2,4-pyrimidinediamine according structural formula (I).

In most situations, the C4 halide is more reactive towards nucleophiles, as illustrated in the Scheme. However, as will be recognized by skilled artisans, the identity of the R⁵ substituent may alter this reactivity. For example, when R⁵ is trifluoromethyl, a 50:50 mixture of 4N-substituted-4-pyrimidineamine 8 and the corresponding 2N-substituted-2-pyrimidineamine is obtained. Regardless of the identity of the R⁵ substituent, the regioselectivity of the reaction can be controlled by adjusting the solvent and other synthetic conditions (such as temperature), as is well-known in the art.

The reactions depicted in Scheme (I) may proceed more quickly when the reaction mixtures are heated via microwave. When heating in this fashion, the following conditions may be used: heat to 175° C. in ethanol for 5-20 min. in a Smith Reactor (Personal Chemistry) in a sealed tube (at 20 bar pressure).

The uracil or thiouracil 2 starting materials may be purchased from commercial sources or prepared using standard techniques of organic chemistry. Commercially available uracils and thiouracils that can be used as starting materials in Scheme (I) include, by way of example and not limitation, uracil (Aldrich #13,078-8; CAS Registry 66-22-8); 2-thio-uracil (Aldrich #11,558-4; CAS Registry 141-90-2); 2,4-dithiouracil (Aldrich #15,846-1; CAS Registry 2001-93-6); 5-acetouracil (Chem. Sources Int'l 2000; CAS Registry 6214-65-9); 5-azidouracil; 5-aminouracil (Aldrich #85,528-6; CAS Registry 932-52-5); 5-bromouracil (Aldrich #85,247-3; CAS Registry 51-20-7); 5-(trans-2-bromovinyl)-uracil (Aldrich #45,744-2; CAS Registry 69304-49-0); 5-(trans-2-chlorovinyl)-uracil (CAS Registry 81751-48-2); 5-(trans-2-carboxyvinyl)-uracil; uracil-5-carboxylic acid (2,4-dihydroxypyrimidine-5-carboxylic acid hydrate; Aldrich #27,770-3; CAS Registry 23945-44-0); 5-chlorouracil (Aldrich #22,458-8; CAS Registry 1820-81-1); 5-cyanouracil (Chem. Sources Int'l 2000; CAS Registry 4425-56-3); 5-ethyluracil (Aldrich #23,044-8; CAS Registry 4212-49-1); 5-ethenyluracil (CAS Registry 37107-81-6); 5-fluorouracil (Aldrich #85,847-1; CAS Registry 51-21-8); 5-iodouracil (Aldrich #85,785-8; CAS Registry 696-07-1); 5-methyluracil (thymine; Aldrich #13,199-7; CAS Registry 65-71-4); 5-nitrouracil (Aldrich #85,276-7; CAS Registry 611-08-5); uracil-5-sulfamic acid (Chem. Sources Int'l 2000; CAS Registry 5435-16-5); 5-(trifluoromethyl)-uracil (Aldrich #22,327-1; CAS Registry 54-20-6); 5-(2,2,2-trifluoroethyl)-uracil (CAS Registry 155143-31-6); 5-(pentafluoroethyl)-uracil (CAS Registry 60007-38-3); 6-aminouracil (Aldrich #A5060-6; CAS Registry 873-83-6) uracil-6-carboxylic acid (orotic acid; Aldrich #0-840-2; CAS Registry 50887-69-9); 6-methyluracil (Aldrich #D11,520-7; CAS Registry 626-48-2); uracil-5-amino-6-carboxylic acid (5-aminoorotic acid; Aldrich #19,121-3; CAS Registry #7164-43-4); 6-amino-5-nitrosouracil (6-amino-2,4-dihydroxy-5-nitrosopyrimidine; Aldrich #27,689-8; CAS Registry 5442-24-0); uracil-5-fluoro-6-carboxylic acid (5-fluoroorotic acid; Aldrich #42,513-3; CAS Registry 00000-00-0); and uracil-5-nitro-6-carboxylic acid (5-nitroorotic acid; Aldrich #18,528-0; CAS Registry 600779-49-9). Additional 5-, 6- and 5,6-substituted uracils and/or thiouracils are available from General Intermediates of Canada, Inc., Edmonton, Alberta, CA and/or Interchim, France or may be prepared using standard techniques. Myriad textbook references teaching suitable synthetic methods are provided infra.

Amines 10 may be purchased from commercial sources or, alternatively, may be synthesized utilizing standard techniques. For example, suitable amines may be synthesized from nitro precursors using standard chemistry. See also Vogel, 1989, Practical Organic Chemistry, Addison Wesley Longman, Ltd. and John Wiley & Sons, Inc. Amines 6 may be synthesized as described, infra, in Schemes (VII) and (VIII).

A specific embodiment of Scheme (I) utilizing 5-fluorouracil (Aldrich #32,937-1) as a starting material is illustrated in Scheme (Ia), below:

In Scheme (Ia), R², R⁴, L¹ and L² are as previously defined for Scheme (I). According to Scheme (Ia), 5-fluorouracil 3 is halogenated with POCl₃ to yield 2,4-dichloro-5-fluoropyrimidine 5. Reaction of 2,4-dichloro-5-fluoropyrimidine 5 with one equivalent of amine 10 (to yield 2-chloro-N-4-substituted-5-fluoro-4-pyrimidineamine 7) followed by one or more equivalents of amine 6.

In still another exemplary embodiment, the 2,4-pyrimidinediamine compounds of the invention may be synthesized from substituted or unsubstituted 2-amino-4-pyrimidinols as illustrated in Scheme (II), below:

In Scheme (II), R², R⁴, R⁵, R⁶, L¹, L² and X are as previously defined for Scheme (I) and Z is a leaving group as discussed in more detail in connection with Scheme III, infra. Referring to Scheme (II), 2-amino-4-pyrimidinol 30 is reacted with amine 6 (or optionally protected amine 21) to yield N2-substituted-4-pyrimidinol 32, which is then halogenated as previously described to yield N2-substituted-4-halo-2-pyrimidineamine 34. Optional deprotection (for example if protected amine 21 was used in the first step) followed by reaction with amine 10 affords a 2,4-pyrimidinediamine according to structural formula (I). Alternatively, pyrimidinol 30 can be reacted with acylating agent 31.

Suitable commercially-available 2-amino-4-pyrimidinols 30 that can be used as starting materials in Scheme (III) include, but are not limited to, 2-amino-6-chloro-4-pyrimidinol hydrate (Aldrich #A4702-8; CAS Registry 00000-00-0) and 2-amino-6-hydroxy-4-pyrimidinol (Aldrich #A5040-1; CAS Registry 56-09-7). Other 2-amino-4-pyrimidinols 30 useful as starting materials in Scheme (III) are available from General Intermediates of Canada, Inc., Edmonton, Alberta, CA and/or Interchim, France or may be prepared using standard techniques. Myriad textbook references teaching suitable synthetic methods are provided infra.

In still another exemplary embodiment, the 2,4-pyrimidinediamine compounds of the invention can be prepared from 2-chloro-4-aminopyrimidines or 2-amino-4-chloropyrimidines as illustrated in Scheme (III), below:

In Scheme (III), R², R⁴, R⁵, R⁶, L¹ and L² are as defined for Scheme (I) and Z is a leaving groups such as, for example, a halogen, methanesulfonyloxy, trifluoromethanesulfonyloxy, p-toluenesulfonyloxy, benzenesulfonlyoxy, etc. Referring to Scheme (III), 2-amino-4-chloropyrimidine 50 is reacted with amino 10 to yield 4N-substituted-2-pyrimidineamine 52 which, following reaction with compound 31 or amine 6, yields a 2,4-pyrimidinediamine according to structural formula (I). Alternatively, 2-chloro-4-amino-pyrimidine 54 may be reacted with compound 44 followed by amine 6 to yield a compound according to structural formula (I).

A variety of pyrimidines 50 and 54 suitable for use as starting materials in Scheme (V) are commercially available, including by way of example and not limitation, 2-amino-4,6-dichloropyrimidine (Aldrich #A4860-1; CAS Registry 56-05-3); 2-amino-4-chloro-6-methoxy-pyrimidine (Aldrich #51,864-6; CAS Registry 5734-64-5); 2-amino-4-chloro-6-methylpyrimidine (Aldrich #12,288-2; CAS Registry 5600-21-5); and 2-amino-4-chloro-6-methylthiopyrimidine (Aldrich #A4600-5; CAS Registry 1005-38-5). Additional pyrimidine starting materials are available from General Intermediates of Canada, Inc., Edmonton, Alberta, CA and/or Interchim, France or may be prepared using standard techniques. Myriad textbook references teaching suitable synthetic methods are provided infra.

Alternatively, 4-chloro-2-pyrimidineamines 50 may be prepared as illustrated in Scheme (IV):

In Scheme (IV), R⁵ and R⁶ are as previously defined for structural formula (I). In Scheme (IV), dicarbonyl 53 is reacted with guanidine to yield 2-pyrimidineamine 51. Reaction with peracids like m-chloroperbenzoic acid, trifluoroperacetic acid or urea hydrogen peroxide complex yields N-oxide 55, which is then halogenated to give 4-chloro-2-pyrimidineamine 50. The corresponding 4-halo-2-pyrimidineamines may be obtained by using suitable halogenation reagents.

As will be recognized by skilled artisans, spiro 2,4-pyrimidinediamines, synthesized via the exemplary methods described above or by other well-known means, may also be utilized as starting materials and/or intermediates to synthesize additional spiro 2,4-pyrimidinediamine compounds. A specific example is illustrated in Scheme (V), below:

In Scheme (V), R4, R5, R6, L2 and Ra are as previously defined for structural formula (I). Each Ra′ is independently an Ra, and may be the same or different from the illustrated Ra. Referring to Scheme (V), carboxylic acid or ester 100 may be converted to amide 104 by reaction with amine 102. In amine 102, Ra□ may be the same or different than Ra of acid or ester 100. Similarly, carbonate ester 106 may be converted to carbamate 108.

A second specific example is illustrated in Scheme (VI), below:

In Scheme (VI), R⁴, R⁵, R⁶, L² and R^(c) are as previously defined for structural formula (I). Referring to Scheme (VI), amide 110 or 116 may be converted to amine 114 or 118, respectively, by borane reduction with borane methylsulfide complex 112. Other suitable reactions for synthesizing spiro 2,4-pyrimidinediamine compounds from spiro 2,4-pyrimidinediamine starting materials will be apparent to those of skill in the art.

Scheme (VII) describes the preparation of spiro heterocylic aryl amines corresponding to compound 10 (i.e., R⁴-L²-NH₂). In Scheme (VII), infra, U is —SH, —NHR^(e) or —OH, V is —NO₂, —NHR^(e), —OR^(e) or —SR^(e), D is hydrogen, —NO₂, or NHR^(e), each R^(e) is independently a protecting group or hydrogen, B is a leaving group such as halogen, mesylate, tosylate, etc., T and P are independently —NR^(e)—, —S—, or —O—, each M is independently a leaving group such as halogen, mesylate, tosylate, etc. or OR^(e), R³¹, R³⁵, X, Y, Z and o are as previously defined, supra.

Referring to Scheme (VII), compound 120, is alkylated with ester 132 to provide after intramolecular cyclization, the annelation product 134. Alkylation of 134 with bifunctional agent 124 provides the monalkyl product 136 which may be intramolecularly cyclized to yield 130 which may be converted to compound 132 by conventional methods known to the skilled artisan. For example, sulfides (i.e., where T and/or P are sulfur) and amines (i.e., where T and/or P are nitrogen) may be converted to sulfoxides, sulforates, sulfonamides, alkylamines, arylamines and protected amines by routine synthetic methods. The various embodiments of substituent D of compound 130 may be interconverted, as H may be converted to NO₂ by nitration, NO₂ to NH₂ by reduction, etc. Finally, as is also known in the art, the carbonyl group in compound 130 may be converted to the dihydro compound by reduction with conventional reagents (e.g., lithium aluminum hydride). In some embodiments of compound 124, one M is halogen and the other M is OR^(e). Accordingly in some embodiments, group M in compound 136 is either a leaving group or may be converted to a leaving group (i.e., when M is OR^(e)) by conventional methods.

Although many of the synthetic schemes discussed above do not illustrate the use of protecting groups, skilled artisans will recognize that in some instances substituents R², R⁴, R⁵, R⁶, L¹ and/or L² may include functional groups requiring protection. The exact identity of the protecting group used will depend upon, among other things, the identity of the functional group being protected and the reaction conditions used in the particular synthetic scheme, and will be apparent to those of skill in the art. Guidance for selecting protecting groups and chemistries for their attachment and removal suitable for a particular application can be found, for example, in Greene & Wuts, Protective Groups in Organic Synthesis, 3d Edition, John Wiley & Sons, Inc., New York (1999).

Prodrugs according to structural formula (II) may be prepared by routine modification of the above-described methods. Alternatively, such prodrugs may be prepared by reacting a suitably protected 2,4-pyrimidinediamine of structural formula (I) with a suitable progroup. Conditions for carrying out such reactions and for deprotecting the product to yield a prodrug of formula (II) are well-known.

Myriad references teaching methods useful for synthesizing pyrimidines generally, as well as starting materials described in Schemes (I)-(VIII), are known in the art. For specific guidance, the reader is referred to Brown, D. J., “The Pyrimidines”, in The Chemistry of Heterocyclic Compounds, Volume 16 (Weissberger, A., Ed.), 1962, Interscience Publishers, (A Division of John Wiley & Sons), New York (“Brown I”); Brown, D. J., “The Pyrimidines”, in The Chemistry of Heterocyclic Compounds, Volume 16, Supplement I (Weissberger, A. and Taylor, E. C., Ed.), 1970, Wiley-Interscience, (A Division of John Wiley & Sons), New York (Brown II”); Brown, D. J., “The Pyrimidines”, in The Chemistry of Heterocyclic Compounds, Volume 16, Supplement II (Weissberger, A. and Taylor, E. C., Ed.), 1985, An Interscience Publication (John Wiley & Sons), New York (“Brown III”); Brown, D. J., “The Pyrimidines” in The Chemistry of Heterocyclic Compounds, Volume 52 (Weissberger, A. and Taylor, E. C., Ed.), 1994, John Wiley & Sons, Inc., New York, pp. 1-1509 (Brown IV”); Kenner, G. W. and Todd, A., in Heterocyclic Compounds, Volume 6, (Elderfield, R. C., Ed.), 1957, John Wiley, New York, Chapter 7 (pyrimidines); Paquette, L. A., Principles of Modern Heterocyclic Chemistry, 1968, W. A. Benjamin, Inc., New York, pp. 1-401 (uracil synthesis pp. 313, 315; pyrimidine synthesis pp. 313-316; amino pyrimidine synthesis pp. 315); Joule, J. A., Mills, K. and Smith, G. F., Heterocyclic Chemistry, 3^(rd) Edition, 1995, Chapman and Hall, London, UK, pp. 1-516; Vorbrüggen, H. and Ruh-Pohlenz, C., Handbook of Nucleoside Synthesis, John Wiley & Sons, New York, 2001, pp. 1-631 (protection of pyrimidines by acylation pp. 90-91; silylation of pyrimidines pp. 91-93); Joule, J. A., Mills, K. and Smith, G. F., Heterocyclic Chemistry, 4^(th) Edition, 2000, Blackwell Science, Ltd, Oxford, UK, pp. 1-589; and Comprehensive Organic Synthesis, Volumes 1-9 (Trost, B. M. and Fleming, I., Ed.), 1991, Pergamon Press, Oxford, UK.

It should be understood by the skilled artisan that in Schemes I through VIII, the N4 nitrogen can be substituted by R^(4c) as described throughout the specification and in the examples provided herein.

6.5 Inhibition of Fc Receptor Signal Cascades

Active spiro 2,4-pyrimidinediamine compounds described herein may inhibit Fc receptor signaling cascades that lead to, among other things, degranulation of cells. As a specific example, the compounds inhibit the FcεRI and/or FcγRI signal cascades that lead to degranulation of immune cells such as neutrophil, eosinophil, mast and/or basophil cells. Both mast and basophil cells play a central role in allergen-induced disorders, including, for example, allergic rhinitis and asthma. Referring to FIG. 1, upon exposure allergens, which may be, among other things, pollen or parasites, allergen-specific IgE antibodies are synthesized by B-cells activated by IL-4 (or IL-13) and other messengers to switch to IgE class specific antibody synthesis. These allergen-specific IgEs bind to the high affinity FcεRI. Upon binding of antigen, the FcεR1-bound IgEs are cross-linked and the IgE receptor signal transduction pathway is activated, which leads to degranulation of the cells and consequent release and/or synthesis of a host of chemical mediators, including histamine, proteases (e.g., tryptase and chymase), lipid mediators such as leukotrienes (e.g., LTC4), platelet-activating factor (PAF) and prostaglandins (e.g., PGD2) and a series of cytokines, including TNF-α, IL-4, IL-13, IL-5, IL-6, IL-8, GMCSF, VEGF and TGF-β. The release and/or synthesis of these mediators from mast and/or basophil cells accounts for the early and late stage responses induced by allergens, and is directly linked to downstream events that lead to a sustained inflammatory state.

The molecular events in the FcεRI signal transduction pathway that lead to release of preformed mediators via degranulation and release and/or synthesis of other chemical mediators are well-known and are illustrated in FIG. 2. Referring to FIG. 2, the FcεRI is a heterotetrameric receptor composed of an IgE-binding alpha-subunit, a beta subunit, and two gamma subunits (gamma homodimer). Cross-linking of FcεRI-bound IgE by multivalent binding agents (including, for example IgE-specific allergens or anti-IgE antibodies or fragments) induces the rapid association and activation of the Src-related kinase Lyn. Lyn phosphorylates immunoreceptor tyrosine-based activation motifs (ITAMS) on the intracellular beta and gamma subunits, which leads to the recruitment of additional Lyn to the beta subunit and Syk kinase to the gamma homodimer. These receptor-associated kinases, which are activated by intra- and intermolecular phosphorylation, phosphorylate other components of the pathway, such as the Btk kinase, LAT, and phospholipase C-gamma PLC-gamma). Activated PLC-gamma initiates pathways that lead to protein kinase C activation and Ca²⁺ mobilization, both of which are required for degranulation. FcεR1 cross-linking also activates the three major classes of mitogen activated protein (MAP) kinases, i.e. ERK1/2, JNK1/2, and p38. Activation of these pathways is important in the transcriptional regulation of proinflammatory mediators, such as TNF-α and IL-6, as well as the lipid mediator leukotriene CA (LTC4).

Although not illustrated, the FcγRI signaling cascade is believed to share some common elements with the FceRI signaling cascade. Importantly, like FcεRI, the FcγRI includes a gamma homodimer that is phosphorylated and recruits Syk, and like FcεRI, activation of the FcγRI signaling cascade leads to, among other things, degranulation. Other Fc receptors that share the gamma homodimer, and which can be regulated by the active 2,4-pyrimidinediamine compounds include, but are not limited to, FcαRI and FcγRIII.

The ability of spiro 2,4-pyrimidinediamine compounds to inhibit Fc receptor signaling cascades may be simply determined or confirmed in in vitro assays. Suitable assays for confirming inhibition of FcεRI-mediated degranulation are provided in the Examples section. In one typical assay, cells capable of undergoing FcεRI-mediated degranulation, such as mast or basophil cells, are first grown in the presence of IL-4, Stem Cell Factor (SCF), IL-6 and IgE to increase expression of the FcεRI, exposed to a 2,4-pyrimidinediamine test compound of the invention and stimulated with anti-IgE antibodies (or, alternatively, an IgE-specific allergen). Following incubation, the amount of a chemical mediator or other chemical agent released and/or synthesized as a consequence of activating the FcεRI signaling cascade may be quantified using standard techniques and compared to the amount of the mediator or agent released from control cells (i.e., cells that are stimulated but that are not exposed to test compound). The concentration of test compound that yields a 50% reduction in the quantity of the mediator or agent measured as compared to control cells is the IC₅₀ of the test compound. The origin of the mast or basophil cells used in the assay will depend, in part, on the desired use for the compounds and will be apparent to those of skill in the art. For example, if the compounds will be used to treat or prevent a particular disease in humans, a convenient source of mast or basophil cells is a human or other animal which constitutes an accepted or known clinical model for the particular disease. Thus, depending upon the particular application, the mast or basophil cells may be derived from a wide variety of animal sources, ranging from, for example, lower mammals such as mice and rats, to dogs, sheep and other mammals commonly employed in clinical testing, to higher mammals such as monkeys, chimpanzees and apes, to humans. Specific examples of cells suitable for carrying out the in vitro assays include, but are not limited to, rodent or human basophil cells, rat basophil leukemia cell lines, primary mouse mast cells (such as bone marrow-derived mouse mast cells “BMMC”) and primary human mast cells isolated from cord blood (“CHMC”) or other tissues such as lung. Methods for isolating and culturing these cell types are well-known or are provided in the Examples section (see, e.g., Demo et al., 1999, Cytometry 36(4):340-348 and copending U.S. application Ser. No. 10/053,355, filed Nov. 8, 2001, the disclosures of which are incorporated herein by reference). Of course, other types of immune cells that degranulate upon activation of the FcεRI signaling cascade may also be used, including, for example, eosinophils.

As will be recognized by skilled artisans, the mediator or agent quantified is not critical. The only requirement is that it be a mediator or agent released and/or synthesized as a consequence of initiating or activating the Fc receptor signaling cascade. For example, referring to FIG. 1, activation of the FcεRI signaling cascade in mast and/or basophil cells leads to numerous downstream events. For example, activation of the FcεRI signal cascade leads to the immediate release (i.e., within 1-3 min. following receptor activation) of a variety of preformed chemical mediators and agents via degranulation. Thus, in one embodiment, the mediator or agent quantified may be specific to granules (i.e., present in granules but not in the cell cytoplasm generally). Examples of granule-specific mediators or agents that can be quantified to determine and/or confirm the activity of a 2,4-pyrimidinediamine compound of the invention include, but are not limited to, granule-specific enzymes such as hexosaminidase and tryptase and granule-specific components such as histamine and serotonin. Assays for quantifying such factors are well-known, and in many instances are commercially available. For example, tryptase and/or hexosaminidase release may be quantified by incubating the cells with cleavable substrates that fluoresce upon cleavage and quantifying the amount of fluorescence produced using conventional techniques. Such cleavable fluorogenic substrates are commercially available. For example, the fluorogenic substrates Z-Gly-Pro-Arg-AMC (Z=benzyloxycarbonyl; AMC=7-amino-4-methylcoumarin; BIOMOL Research Laboratories, Inc., Plymouth Meeting, Pa. 19462, Catalog No. P-142) and Z-Ala-Lys-Arg-AMC (Enzyme Systems Products, a division of ICN Biomedicals, Inc., Livermore, CA 94550, Catalog No. AMC-246) can be used to quantify the amount of tryptase released. The fluorogenic substrate 4-methylumbelliferyl-N-acetyl-β-D-glucosaminide (Sigma, St. Louis, Mo., Catalog #69585) can be used to quantify the amount of hexosaminidase released. Histamine release may be quantified using a commercially available enzyme-linked immunosorbent assay (ELISA) such as Immunotech histamine ELISA assay #IM2015 (Beckman-Coulter, Inc.). Specific methods of quantifying the release of tryptase, hexosaminidase and histamine are provided in the Examples section. Any of these assays may be used to determine or confirm the activity of spiro 2,4-pyrimidinediamine.

Referring again to FIG. 1, degranulation is only one of several responses initiated by the FcεRI signaling cascade. In addition, activation of this signaling pathway leads to the de novo synthesis and release of cytokines and chemokines such as IL-4, IL-5, IL-6, TNF-α, IL-13 and MIP1-α), and release of lipid mediators such as leukotrienes (e.g., LTC4), platelet activating factor (PAF) and prostaglandins. Accordingly, the 2,4-pyrimidinediamine compounds of the invention may also be assessed for activity by quantifying the amount of one or more of these mediators released and/or synthesized by activated cells.

Unlike the granule-specific components discussed above, these “late stage” mediators are not released immediately following activation of the FcεRI signaling cascade. Accordingly, when quantifying these late stage mediators, care should be taken to insure that the activated cell culture is incubated for a time sufficient to result in the synthesis (if necessary) and release of the mediator being quantified. Generally, PAF and lipid mediators such as leukotriene C4 are released 3-30 min. following FcεRI activation. The cytokines and other late stage mediators are released approx. 4-8 hrs. following FcεRI activation. Incubation times suitable for a specific mediator will be apparent to those of skill in the art. Specific guidance and assays are provided in the Examples section.

The amount of a particular late stage mediator released may be quantified using any standard technique. In one embodiment, the amount(s) may be quantified using ELISA assays. ELISA assay kits suitable for quantifying the amount of TNFα, IL-4, IL-5, IL-6 and/or IL-13 released are available from, for example, Biosource International, Inc., Camarillo, Calif. 93012 (see, e.g., Catalog Nos. KHC3011, KHC0042, KHC0052, KHC0061 and KHC0132). ELISA assay kits suitable for quantifying the amount of leukotriene C4 (LTC4) released from cells are available from Cayman Chemical Co., Ann Arbor, Mich. 48108 (see, e.g., Catalog No. 520211).

Typically, active spiro 2,4-pyrimidinediamine compounds will exhibit IC₅₀s with respect to FcεRI-mediated degranulation and/or mediator release or synthesis of about 20 μM or lower, as measured in an in vitro assay, such as one of the in vitro assays described above or in the Examples section. Of course, skilled artisans will appreciate that compounds which exhibit lower IC₅₀s, for example on the order of 10 μM, 1 μM, 100 nM, 10 nM, 1 nM, or even lower, are particularly useful.

Skilled artisans will also appreciate that the various mediators discussed above may induce different adverse effects or exhibit different potencies with respect to the same adverse effect. For example, the lipid mediator LTC4 is a potent vasoconstrictor—it is approximately 1000-fold more potent at inducing vasoconstriction than histamine. As another example, in addition to mediating atopic or Type I hypersensitivity reactions, cytokines can also cause tissue remodeling and cell proliferation. Thus, although compounds that inhibit release and/or synthesis of any one of the previously discussed chemical mediators are useful, skilled artisans will appreciate that compounds which inhibit the release and/or synthesis of a plurality, or even all, of the previously described mediators find particular use, as such compounds are useful for ameliorating or avoiding altogether a plurality, or even all, of the adverse effects induced by the particular mediators. For example, compounds which inhibit the release of all three types of mediators-granule-specific, lipid and cytokine-are useful for treating or preventing immediate Type I hypersensitivity reactions as well as the chronic symptoms associated therewith.

Compounds described herein capable of inhibiting the release of more than one type of mediator (e.g., granule-specific or late stage) may be identified by determining the IC₅₀ with respect to a mediator representative of each class using the various in vitro assays described above (or other equivalent in vitro assays). Compounds which are capable of inhibiting the release of more than one mediator type will typically exhibit an IC₅₀ for each mediator type tested of less than about 20 μM. For example, a compound which exhibits an IC₅₀ of 1 μM with respect to histamine release (IC₅₀ ^(histamine)) and an IC₅₀ of 1 nM with respect to leukotriene LTC4 synthesis and/or release (IC₅₀ ^(LTC4)) inhibits both immediate (granule-specific) and late stage mediator release. As another specific example, a compound that exhibits an IC₅₀ ^(tryptase) of 10 μM, an IC₅₀ ^(LTC4) of 1 μM and an IC₅₀ ^(IL-4) of 1 μM inhibits immediate (granule-specific), lipid and cytokine mediator release. Although the above specific examples utilize the IC₅₀s of one representative mediator of each class, skilled artisans will appreciate that the IC₅₀s of a plurality, or even all, mediators comprising one or more of the classes may be obtained. The quantity(ies) and identity(ies) of mediators for which IC₅₀ data should be ascertained for a particular compound and application will be apparent to those of skill in the art.

Similar assays may be utilized to confirm inhibition of signal transduction cascades initiated by other Fc receptors, such as FcαRI, FcγRI and/or FcγRIII signaling, with routine modification. For example, the ability of the compounds to inhibit FcγRI signal transduction may be confirmed in assays similar to those described above, with the exception that the FcγRI signaling cascade is activated, for example by incubating the cells with IgG and an IgG-specific allergen or antibody, instead of IgE and an IgE-specific allergen or antibody. Suitable cell types, activating agents and agents to quantify to confirm inhibition of other Fc receptors, such as Fc receptors that comprise a gamma homodimer, will be apparent to those of skill in the art.

One particularly useful class of compounds includes those spiro 2,4-pyrimidinediamine compounds that inhibit the release of immediate granule-specific mediators and late stage mediators with approximately equivalent IC₅₀s. By approximately equivalent is meant that the IC₅₀s for each mediator type are within about a 10-fold range of one another. Another particularly useful class of compounds includes those spiro 2,4-pyrimidinediamine compounds that inhibit the release of immediate granule-specific mediators, lipid mediators and cytokine mediators with approximately equivalent IC₅₀s. In a specific embodiment, such compounds inhibit the release of the following mediators with approximately equivalent IC₅₀s: histamine, tryptase, hexosaminidase, IL-4, IL-5, IL-6, IL-13, TNFα and LTC4. Such compounds are particularly useful for, among other things, ameliorating or avoiding altogether both the early and late stage responses associated with atopic or immediate Type I hypersensitivity reactions.

Ideally, the ability to inhibit the release of all desired types of mediators will reside in a single compound. However, mixtures of compounds can also be identified that achieve the same result. For example, a first compound which inhibits the release of granule specific mediators may be used in combination with a second compound which inhibits the release and/or synthesis of cytokine mediators.

In addition to the FcεRI or FcγRI degranulation pathways discussed above, degranulation of mast and/or basophil cells can be induced by other agents. For example, ionomycin, a calcium ionophore that bypasses the early FcεRI or FcγRI signal transduction machinery of the cell, directly induces a calcium flux that triggers degranulation. Referring again to FIG. 2, activated PLCγ initiates pathways that lead to, among other things, calcium ion mobilization and subsequent degranulation. As illustrated, this Ca²⁺ mobilization is triggered late in the FcεRI signal transduction pathway. As mentioned above, and as illustrated in FIG. 3, ionomycin directly induces Ca²⁺ mobilization and a Ca²⁺ flux that leads to degranulation. Other ionophores that induce degranulation in this manner include A23187. The ability of granulation-inducing ionophores such as ionomycin to bypass the early stages of the FcεRI and/or FcγRI signaling cascades may be used as a counter screen to identify active compounds of the invention that specifically exert their degranulation-inhibitory activity by blocking or inhibiting the early FcεRI or FcγRI signaling cascades, as discussed above. Compounds which specifically inhibit such early FcεRI or FcγRI-mediated degranulation inhibit not only degranulation and subsequent rapid release of histamine, tryptase and other granule contents, but also inhibit the pro-inflammatory activation pathways causing the release of TNFα, IL-4, IL-13 and the lipid mediators such as LTC4. Thus, compounds which specifically inhibit such early FcεRI and/or FcγRI-mediated degranulation block or inhibit not only acute atopic or Type I hypersensitivity reactions, but also late responses involving multiple inflammatory mediators.

Compounds described herein that specifically inhibit early FcεRI and/or FcγRI-mediated degranulation are those compounds that inhibit FcεRI and/or FcγRI-mediated degranulation (for example, have an IC₅₀ of less than about 20 μM with respect to the release of a granule-specific mediator or component as measured in an in vitro assay with cells stimulated with an IgE or IgG binding agent) but that do not appreciably inhibit ionophore-induced degranulation. In one embodiment, compounds are considered to not appreciably inhibit ionophore-induced degranulation if they exhibit an IC₅₀ of ionophore-induced degranulation of greater than about 20 μM, as measured in an in vitro assay. Of course, active compounds that exhibit even higher IC₅₀'s of ionophore-induced degranulation, or that do not inhibit ionophore-induced degranulation at all, are particularly useful. In another embodiment, compounds are considered to not appreciably inhibit ionophore-induced degranulation if they exhibit a greater than 10-fold difference in their IC₅₀s of FcεRI and/or FcγRI-mediated degranulation and ionophore-induced degranulation, as measured in an in vitro assay. Assays suitable for determining the IC₅₀ of ionophore-induced degranulation include any of the previously-described degranulation assays, with the modification that the cells are stimulated or activated with a degranulation-inducing calcium ionophore such as ionomycin or A23187 (A.G. Scientific, San Diego, Calif.) instead of anti-IgE antibodies or an IgE-specific allergen. Specific assays for assessing the ability of a particular spiro 2,4-pyrimidinediamine compound of the invention to inhibit ionophore-induced degranulation are provided in the Examples section.

As will be recognized by skilled artisans, compounds which exhibit a high degree of selectivity of FcεRI-mediated degranulation find particular use, as such compounds selectively target the FcεRI cascade and do not interfere with other degranulation mechanisms. Similarly, compounds which exhibit a high degree of selectivity of FcγRI-mediated degranulation find particular use, as such compounds selectively target the FcγRI cascade and do not interfere with other degranulation mechanisms. Compounds which exhibit a high degree of selectivity are generally 10-fold or more selective for FcεRI- or FcγRI-mediated degranulation over ionophore-induced degranulation, such as ionomycin-induced degranulation.

Accordingly, the activity of spiro 2,4-pyrimidinediamine compounds may also be confirmed in biochemical or cellular assays of Syk kinase activity. Referring again to FIG. 2, in the FcεRI signaling cascade in mast and/or basophil cells, Syk kinase phosphorylates LAT and PLC-gamma1, which leads to, among other things, degranulation. Any of these activities may be used to confirm the activity of spiro 2,4-pyrimidinediamine compounds. In one embodiment, the activity is confirmed by contacting an isolated Syk kinase, or an active fragment thereof with a spiro 2,4-pyrimidinediamine compound in the presence of a Syk kinase substrate (e.g., a synthetic peptide or a protein that is known to be phosphorylated by Syk in a signaling cascade) and assessing whether the Syk kinase phosphorylated the substrate. Alternatively, the assay may be carried out with cells that express a Syk kinase. The cells may express the Syk kinase endogenously or they may be engineered to express a recombinant Syk kinase. The cells may optionally also express the Syk kinase substrate. Cells suitable for performing such confirmation assays, as well as methods of engineering suitable cells will be apparent to those of skill in the art. Specific examples of biochemical and cellular assays suitable for confirming the activity of spiro 2,4-pyrimidinediamine compounds are provided in the Examples section.

Generally, compounds that are Syk kinase inhibitors will exhibit an IC₅₀ with respect to a Syk kinase activity, such as the ability of Syk kinase to phosphorylate a synthetic or endogenous substrate, in an in vitro or cellular assay in the range of about 20 μM or less. Skilled artisans will appreciate that compounds that exhibit lower IC50s, such as in the range of 10 μM, 1 μM, 100 nM, 10 nM, 1 nM, or even lower, are particularly useful.

6.6 Uses and Compositions

As previously discussed, active compounds inhibit Fc receptor signaling cascades, especially those Fc receptors including a gamma homodimer, such as the FcεRI and/or FcγRI signaling cascades, that lead to, among other things, the release and/or synthesis of chemical mediators from cells, either via degranulation or other processes. As also discussed, the active compounds are also potent inhibitors of Syk kinase. As a consequence of these activities, the active compounds of the invention may be used in a variety of in vitro, in vivo and ex vivo contexts to regulate or inhibit Syk kinase, signaling cascades in which Syk kinase plays a role, Fc receptor signaling cascades, and the biological responses effected by such signaling cascades. For example, in one embodiment, the compounds may be used to inhibit Syk kinase, either in vitro or in vivo, in virtually any cell type expressing Syk kinase. They may also be used to regulate signal transduction cascades in which Syk kinase plays a role. Such Syk-dependent signal transduction cascades include, but are not limited to, the FcεRI, FcγRI, FcγRIII, BCR and integrin signal transduction cascades. The compounds may also be used in vitro or in vivo to regulate, and in particular inhibit, cellular or biological responses effected by such Syk-dependent signal transduction cascades. Such cellular or biological responses include, but are not limited to, respiratory burst, cellular adhesion, cellular degranulation, cell spreading, cell migration, cell aggregation, phagocytosis, cytokine synthesis and release, cell maturation and Ca²⁺ flux. Importantly, the compounds may be used to inhibit Syk kinase in vivo as a therapeutic approach towards the treatment or prevention of diseases mediated, either wholly or in part, by a Syk kinase activity. Non-limiting examples of Syk kinase mediated diseases that may be treated or prevented with the compounds are those discussed in more detail, below.

In another embodiment, the active compounds may be used to regulate or inhibit the Fc receptor signaling cascades and/or FcεRI- and/or FcγRI-mediated degranulation as a therapeutic approach towards the treatment or prevention of diseases characterized by, caused by and/or associated with the release or synthesis of chemical mediators of such Fc receptor signaling cascades or degranulation. Such treatments may be administered to animals in veterinary contexts or to humans. Diseases that are characterized by, caused by or associated with such mediator release, synthesis or degranulation, and that can therefore be treated or prevented with the active compounds include, by way of example and not limitation, atopy or anaphylactic hypersensitivity or allergic reactions, allergies (e.g., allergic conjunctivitis, allergic rhinitis, atopic asthma, atopic dermatitis and food allergies), low grade scarring (e.g., of scleroderma, increased fibrosis, keloids, post-surgical scars, pulmonary fibrosis, vascular spasms, migraine, reperfusion injury and post myocardial infarction), diseases associated with tissue destruction (e.g., of COPD, cardiobronchitis and post myocardial infarction), diseases associated with tissue inflammation (e.g., irritable bowel syndrome, spastic colon and inflammatory bowel disease), inflammation and scarring.

In addition to the myriad diseases discussed above, spiro 2,4-pyrimidinediamine compounds described herein may also be useful for the treatment or prevention of autoimmune diseases, as well as the various symptoms associated with such diseases. The types of autoimmune diseases that may be treated or prevented with the 2,4-pyrimidinediamine compounds generally include those disorders involving tissue injury that occurs as a result of a humoral and/or cell-mediated response to immunogens or antigens of endogenous and/or exogenous origin. Such diseases are frequently referred to as diseases involving the nonanaphylactic (i.e., Type II, Type III and/or Type IV) hypersensitivity reactions.

As discussed previously, Type I hypersensitivity reactions generally result from the release of pharmacologically active substances, such as histamine, from mast and/or basophil cells following contact with a specific exogenous antigen. As mentioned above, such Type I reactions play a role in numerous diseases, including allergic asthma, allergic rhinitis, etc.

Type II hypersensitivity reactions (also referred to as cytotoxic, cytolytic complement-dependent or cell-stimulating hypersensitivity reactions) result when immunoglobulins react with antigenic components of cells or tissue, or with an antigen or hapten that has become intimately coupled to cells or tissue. Diseases that are commonly associated with Type II hypersensitivity reactions include, but are not limited, to autoimmune hemolytic anemia, erythroblastosis fetalis and Goodpasture's disease.

Type III hypersensitivity reactions, (also referred to as toxic complex, soluble complex, or immune complex hypersensitivity reactions) result from the deposition of soluble circulating antigen-immunoglobulin complexes in vessels or in tissues, with accompanying acute inflammatory reactions at the site of immune complex deposition. Non-limiting examples of prototypical Type III reaction diseases include the Arthus reaction, rheumatoid arthritis, serum sickness, systemic lupus erythematosis, certain types of glomerulonephritis, multiple sclerosis and bullous pemphingoid.

Type IV hypersensitivity reactions (frequently called cellular, cell-mediated, delayed, or tuberculin-type hypersensitivity reactions) are caused by sensitized T-lymphocytes which result from contact with a specific antigen. Non-limiting examples of diseases cited as involving Type IV reactions are contact dermatitis and allograft rejection.

Autoimmune diseases associated with any of the above nonanaphylactic hypersensitivity reactions may be treated or prevented with spiro 2,4-pyrimidinediamine. In particular, the methods may be used to treat or prevent those autoimmune diseases frequently characterized as single organ or single cell-type autoimmune disorders including, but not limited to: Hashimoto's thyroiditis, autoimmune hemolytic anemia, autoimmune atrophic gastritis of pernicious anemia, autoimmune encephalomyelitis, autoimmune orchitis, Goodpasture's disease, autoimmune thrombocytopenia, sympathetic ophthalmia, myasthenia gravis, Graves' disease, primary biliary cirrhosis, chronic aggressive hepatitis, ulcerative colitis and membranous glomerulopathy, as well as those autoimmune diseases frequently characterized as involving systemic autoimmune disorder, which include but are not limited to: systemic lupus erythematosis, rheumatoid arthritis, Sjogren's syndrome, Reiter's syndrome, polymyositis-dermatomyositis, systemic sclerosis, polyarteritis nodosa, multiple sclerosis and bullous pemphigoid.

It will be appreciated by skilled artisans that many of the above-listed autoimmune diseases are associated with severe symptoms, the amelioration of which provides significant therapeutic benefit even in instances where the underlying autoimmune disease may not be ameliorated. Many of these symptoms, as well as their underlying disease states, result as a consequence of activating the FcγR signaling cascade in monocyte cells. As the 2,4-pyrimidinediamine compounds described herein are potent inhibitors of such FcγR signaling in monocytes and other cells, the methods find use in the treatment and/or prevention of myriad adverse symptoms associated with the above-listed autoimmune diseases.

As a specific example, rheumatoid arthritis (RA) typically results in swelling, pain, loss of motion and tenderness of target joints throughout the body. RA is characterized by chronically inflamed synovium that is densely crowded with lymphocytes. The synovial membrane, which is typically one cell layer thick, becomes intensely cellular and assumes a form similar to lymphoid tissue, including dendritic cells, T-, B- and NK cells, macrophages and clusters of plasma cells. This process, as well as a plethora of immunopathological mechanisms including the formation of antigen-immunoglobulin complexes, eventually result in destruction of the integrity of the joint, resulting in deformity, permanent loss of function and/or bone erosion at or near the joint. The methods may be used to treat or ameliorate any one, several or all of these symptoms of RA. Thus, in the context of RA, the methods are considered to provide therapeutic benefit (discussed more generally, infra) when a reduction or amelioration of any of the symptoms commonly associated with RA is achieved, regardless of whether the treatment results in a concomitant treatment of the underlying RA and/or a reduction in the amount of circulating rheumatoid factor (“RF”).

As another specific example, systemic lupus erythematosis (“SLE”) is typically associated with symptoms such as fever, joint pain (arthralgias), arthritis, and serositis (pleurisy or pericarditis). In the context of SLE, the methods are considered to provide therapeutic benefit when a reduction or amelioration of any of the symptoms commonly associated with SLE are achieved, regardless of whether the treatment results in a concomitant treatment of the underlying SLE.

As another specific example, multiple sclerosis (“MS”) cripples the patient by disturbing visual acuity; stimulating double vision; disturbing motor functions affecting walking and use of the hands; producing bowel and bladder incontinence; spasticity; and sensory deficits (touch, pain and temperature sensitivity). In the context of MS, the methods are considered to provide therapeutic benefit when an improvement or a reduction in the progression of any one or more of the crippling effects commonly associated with MS is achieved, regardless of whether the treatment results in a concomitant treatment of the underlying MS.

When used to treat or prevent such diseases, the active compounds may be administered singly, as mixtures of one or more active compounds or in mixture or combination with other agents useful for treating such diseases and/or the symptoms associated with such diseases. The active compounds may also be administered in mixture or in combination with agents useful to treat other disorders or maladies, such as steroids, membrane stabilizers, 5LO inhibitors, leukotriene synthesis and receptor inhibitors, inhibitors of IgE isotype switching or IgE synthesis, IgG isotype switching or IgG synthesis, β-agonists, tryptase inhibitors, aspirin, COX inhibitors, methotrexate, anti-TNF drugs, retuxin, PD4 inhibitors, p38 inhibitors, PDE4 inhibitors, and antihistamines, to name a few. The active compounds may be administered per se in the form of prodrugs or as pharmaceutical compositions, comprising an active compound or prodrug.

Pharmaceutical compositions comprising the active compounds described herein (or prodrugs thereof) may be manufactured by means of conventional mixing, dissolving, granulating, dragee-making levigating, emulsifying, encapsulating, entrapping or lyophilization processes. The compositions may be formulated in conventional manner using one or more physiologically acceptable carriers, diluents, excipients or auxiliaries which facilitate processing of the active compounds into preparations which can be used pharmaceutically.

The active compound or prodrug may be formulated in the pharmaceutical compositions per se, or in the form of a hydrate, solvate, N-oxide or pharmaceutically acceptable salt, as previously described. Typically, such salts are more soluble in aqueous solutions than the corresponding free acids and bases, but salts having lower solubility than the corresponding free acids and bases may also be formed.

Pharmaceutical compositions of the invention may take a form suitable for virtually any mode of administration, including, for example, topical, ocular, oral, buccal, systemic, nasal, injection, transdermal, rectal, vaginal, etc., or a form suitable for administration by inhalation or insufflation.

For topical administration, the active compound(s) or prodrug(s) may be formulated as solutions, gels, ointments, creams, suspensions, etc. as are well-known in the art.

Systemic formulations include those designed for administration by injection, e.g., subcutaneous, intravenous, intramuscular, intrathecal or intraperitoneal injection, as well as those designed for transdermal, transmucosal oral or pulmonary administration.

Useful injectable preparations include sterile suspensions, solutions or emulsions of the active compound(s) in aqueous or oily vehicles. The compositions may also contain formulating agents, such as suspending, stabilizing and/or dispersing agent. The formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multidose containers, and may contain added preservatives.

Alternatively, the injectable formulation may be provided in powder form for reconstitution with a suitable vehicle, including but not limited to sterile pyrogen free water, buffer, dextrose solution, etc., before use. To this end, the active compound(s) may be dried by any art-known technique, such as lyophilization, and reconstituted prior to use.

For transmucosal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are known in the art.

For oral administration, the pharmaceutical compositions may take the form of, for example, lozenges, tablets or capsules prepared by conventional means with pharmaceutically acceptable excipients such as binding agents (e.g., pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); fillers (e.g., lactose, microcrystalline cellulose or calcium hydrogen phosphate); lubricants (e.g., magnesium stearate, talc or silica); disintegrants (e.g., potato starch or sodium starch glycolate); or wetting agents (e.g., sodium lauryl sulfate). The tablets may be coated by methods well known in the art with, for example, sugars, films or enteric coatings.

Liquid preparations for oral administration may take the form of, for example, elixirs, solutions, syrups or suspensions, or they may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (e.g., sorbitol syrup, cellulose derivatives or hydrogenated edible fats); emulsifying agents (e.g., lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily esters, ethyl alcohol, cremophore™ or fractionated vegetable oils); and preservatives (e.g., methyl or propyl-p-hydroxybenzoates or sorbic acid). The preparations may also contain buffer salts, preservatives, flavoring, coloring and sweetening agents as appropriate.

Preparations for oral administration may be suitably formulated to give controlled release of the active compound or prodrug, as is well known.

For buccal administration, the compositions may take the form of tablets or lozenges formulated in conventional manner.

For rectal and vaginal routes of administration, the active compound(s) may be formulated as solutions (for retention enemas) suppositories or ointments containing conventional suppository bases such as cocoa butter or other glycerides.

For nasal administration or administration by inhalation or insufflation, the active compound(s) or prodrug(s) can be conveniently delivered in the form of an aerosol spray from pressurized packs or a nebulizer with the use of a suitable propellant, e.g., dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, fluorocarbons, carbon dioxide or other suitable gas. In the case of a pressurized aerosol, the dosage unit may be determined by providing a valve to deliver a metered amount. Capsules and cartridges for use in an inhaler or insufflator (for example capsules and cartridges comprised of gelatin) may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.

A specific example of an aqueous suspension formulation suitable for nasal administration using commercially-available nasal spray devices includes the following ingredients: active compound or prodrug (0.5-20 mg/ml); benzalkonium chloride (0.1-0.2 mg/mL); polysorbate 80 (TWEEN® 80; 0.5-5 mg/ml); carboxymethylcellulose sodium or microcrystalline cellulose (1-15 mg/ml); phenylethanol (1-4 mg/ml); and dextrose (20-50 mg/ml). The pH of the final suspension can be adjusted to range from about pH5 to pH7, with a pH of about pH 5.5 being typical.

Another specific example of an aqueous suspension suitable for administration of the compounds via inhalation, and in particular for such administration of a compound of the invention, contains 1-20 mg/mL of the compound or prodrug, 0.1-1% (v/v) Polysorbate 80 (TWEEN®80), 50 mM citrate and/or 0.9% sodium chloride.

For ocular administration, the active compound(s) or prodrug(s) may be formulated as a solution, emulsion, suspension, etc. suitable for administration to the eye. A variety of vehicles suitable for administering compounds to the eye are known in the art. Specific non-limiting examples are described in U.S. Pat. No. 6,261,547; U.S. Pat. No. 6,197,934; U.S. Pat. No. 6,056,950; U.S. Pat. No. 5,800,807; U.S. Pat. No. 5,776,445; U.S. Pat. No. 5,698,219; U.S. Pat. No. 5,521,222; U.S. Pat. No. 5,403,841; U.S. Pat. No. 5,077,033; U.S. Pat. No. 4,882,150; and U.S. Pat. No. 4,738,851.

For prolonged delivery, the active compound(s) or prodrug(s) can be formulated as a depot preparation for administration by implantation or intramuscular injection. The active ingredient may be formulated with suitable polymeric or hydrophobic materials (e.g., as an emulsion in an acceptable oil) or ion exchange resins, or as sparingly soluble derivatives, e.g., as a sparingly soluble salt. Alternatively, transdermal delivery systems manufactured as an adhesive disc or patch which slowly releases the active compound(s) for percutaneous absorption may be used. To this end, permeation enhancers may be used to facilitate transdermal penetration of the active compound(s). Suitable transdermal patches are described in for example, U.S. Pat. No. 5,407,713; U.S. Pat. No. 5,352,456; U.S. Pat. No. 5,332,213; U.S. Pat. No. 5,336,168; U.S. Pat. No. 5,290,561; U.S. Pat. No. 5,254,346; U.S. Pat. No. 5,164,189; U.S. Pat. No. 5,163,899; U.S. Pat. No. 5,088,977; U.S. Pat. No. 5,087,240; U.S. Pat. No. 5,008,110; and U.S. Pat. No. 4,921,475.

Alternatively, other pharmaceutical delivery systems may be employed. Liposomes and emulsions are well-known examples of delivery vehicles that may be used to deliver active compound(s) or prodrug(s). Certain organic solvents such as dimethylsulfoxide (DMSO) may also be employed, although usually at the cost of greater toxicity.

The pharmaceutical compositions may, if desired, be presented in a pack or dispenser device which may contain one or more unit dosage forms containing the active compound(s). The pack may, for example, comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration.

6.7 Effective Dosages

The active compound(s) or prodrug(s), or compositions thereof, will generally be used in an amount effective to achieve the intended result, for example in an amount effective to treat or prevent the particular disease being treated. The compound(s) may be administered therapeutically to achieve therapeutic benefit or prophylactically to achieve prophylactic benefit. By therapeutic benefit is meant eradication or amelioration of the underlying disorder being treated and/or eradication or amelioration of one or more of the symptoms associated with the underlying disorder such that the patient reports an improvement in feeling or condition, notwithstanding that the patient may still be afflicted with the underlying disorder. For example, administration of a compound to a patient suffering from an allergy provides therapeutic benefit not only when the underlying allergic response is eradicated or ameliorated, but also when the patient reports a decrease in the severity or duration of the symptoms associated with the allergy following exposure to the allergen. As another example, therapeutic benefit in the context of asthma includes an improvement in respiration following the onset of an asthmatic attack, or a reduction in the frequency or severity of asthmatic episodes. Therapeutic benefit also includes halting or slowing the progression of the disease, regardless of whether improvement is realized.

For prophylactic administration, the compound may be administered to a patient at risk of developing one of the previously described diseases. For example, if it is unknown whether a patient is allergic to a particular drug, the compound may be administered prior to administration of the drug to avoid or ameliorate an allergic response to the drug. Alternatively, prophylactic administration may be applied to avoid the onset of symptoms in a patient diagnosed with the underlying disorder. For example, a compound may be administered to an allergy sufferer prior to expected exposure to the allergen. Compounds may also be administered prophylactically to healthy individuals who are repeatedly exposed to agents known to one of the above-described maladies to prevent the onset of the disorder. For example, a compound may be administered to a healthy individual who is repeatedly exposed to an allergen known to induce allergies, such as latex, in an effort to prevent the individual from developing an allergy. Alternatively, a compound may be administered to a patient suffering from asthma prior to partaking in activities which trigger asthma attacks to lessen the severity of, or avoid altogether, an asthmatic episode.

The amount of compound administered will depend upon a variety of factors, including, for example, the particular indication being treated, the mode of administration, whether the desired benefit is prophylactic or therapeutic, the severity of the indication being treated and the age and weight of the patient, the bioavailability of the particular active compound, etc. Determination of an effective dosage is well within the capabilities of those skilled in the art.

Effective dosages may be estimated initially from in vitro assays. For example, an initial dosage for use in animals may be formulated to achieve a circulating blood or serum concentration of active compound that is at or above an IC₅₀ of the particular compound as measured in as in vitro assay, such as the in vitro CHMC or BMMC and other in vitro assays described in the Examples section. Calculating dosages to achieve such circulating blood or serum concentrations taking into account the bioavailability of the particular compound is well within the capabilities of skilled artisans. For guidance, the reader is referred to Fingl & Woodbury, “General Principles,” In: Goodman and Gilman's The Pharmaceutical Basis of Therapeutics, Chapter 1, pp. 1-46, latest edition, Pergamon Press, and the references cited therein.

Initial dosages can also be estimated from in vivo data, such as animal models. Animal models useful for testing the efficacy of compounds to treat or prevent the various diseases described above are well-known in the art. Suitable animal models of hypersensitivity or allergic reactions are described in Foster, 1995, Allergy 50(21Suppl):6-9, discussion 34-38 and Tumas et al., 2001, J. Allergy Clin. Immunol. 107(6):1025-1033. Suitable animal models of allergic rhinitis are described in Szelenyi et al., 2000, Arzneimittelforschung 50(11):1037-42; Kawaguchi et al., 1994, Clin. Exp. Allergy 24(3):238-244 and Sugimoto et al., 2000, Immunopharmacology 48(1):1-7. Suitable animal models of allergic conjunctivitis are described in Carreras et al., 1993, Br. J. Ophthalmol. 77(8):509-514; Saiga et al., 1992, Ophthalmic Res. 24(1):45-50; and Kunert et al., 2001, Invest. Ophthalmol. Vis. Sci. 42(11):2483-2489. Suitable animal models of systemic mastocytosis are described in O'Keefe et al., 1987, J. Vet. Intern. Med. 1(2):75-80 and Bean-Knudsen et al., 1989, Vet. Pathol. 26(1):90-92. Suitable animal models of hyper IgE syndrome are described in Claman et al., 1990, Clin. Immunol. Immunopathol. 56(1):46-53. Suitable animal models of B-cell lymphoma are described in Hough et al., 1998, Proc. Natl. Acad. Sci. USA 95:13853-13858 and Hakim et al., 1996, J. Immunol. 157(12):5503-5511. Suitable animal models of atopic disorders such as atopic dermatitis, atopic eczema and atopic asthma are described in Chan et al., 2001, J. Invest. Dermatol. 117(4):977-983 and Suto et al., 1999, Int. Arch. Allergy Immunol. 120(Suppl 1):70-75. Ordinarily skilled artisans can routinely adapt such information to determine dosages suitable for human administration. Additional suitable animal models are described in the Examples section.

Dosage amounts will typically be in the range of from about 0.0001 or 0.001 or 0.01 mg/kg/day to about 100 mg/kg/day, but may be higher or lower, depending upon, among other factors, the activity of the compound, its bioavailability, the mode of administration and various factors discussed above. Dosage amount and interval may be adjusted individually to provide plasma levels of the compound(s) which are sufficient to maintain therapeutic or prophylactic effect. For example, the compounds may be administered once per week, several times per week (e.g., every other day), once per day or multiple times per day, depending upon, among other things, the mode of administration, the specific indication being treated and the judgment of the prescribing physician. In cases of local administration or selective uptake, such as local topical administration, the effective local concentration of active compound(s) may not be related to plasma concentration. Skilled artisans will be able to optimize effective local dosages without undue experimentation.

Preferably, the compound(s) will provide therapeutic or prophylactic benefit without causing substantial toxicity. Toxicity of the compound(s) may be determined using standard pharmaceutical procedures. The dose ratio between toxic and therapeutic (or prophylactic) effect is the therapeutic index. Compounds(s) that exhibit high therapeutic indices are preferred.

The invention having been described, the following examples are offered by way of illustration and not limitation.

7. EXAMPLES

7.2 Spiro 2,4-Pyrimidinediamine Compounds

7.2.1 Racemic-2-(2-t-Butyldimethylsiloxyethyl)-6-nitro-3-oxo-4H-benz[1,4]oxazine

To solution of 4.8 g racemic-2-(2-hydroxyethyl)-6-nitro-3-oxo-4H-benz[1,4]oxazine in dimethylformamide (100 mL) and 3.4 mL diethylisopropylamine at 0° C. was added 4.7 g tert-butyldimethylsilylchloride. The reaction mixture was stirred at 0° C. for 20 minutes, at room temperature for 3 hour, concentrated and the resulting residue was partitioned between sodium bicarbonate solution and EtOAc. The aqueous phase was extracted with EtOAc and the combined organics washed with water, brine then dried over MgSO4. The solvent was removed by in vacuo and the crude material purified by column chromatography (hexanes/EtOAc) to yield 1 g of the desired product racemic-2-(2-t-butyldimethylsiloxyethyl)-6-nitro-3-oxo-4H-benz[1,4]oxazine MS (m/e): 353 (MH⁺).

7.2.2 Racemic-2-2-t-Butyldimethylsiloxyethyl-6-nitro-3-oxo-4-p-methoxybenzyl-benz[1,4]oxazine

A solution of 450 mg of racemic-2-(2-t-butyldimethylsiloxyethyl)-6-nitro-3-oxo-4-(p-methoxybenzyl)-benz[1,4]oxazine in 25 mL of 1% concentrated HCl in EtOH was stirred for 2 h. The solvent was removed by rotary evaporation to yield 370 mg of the desired product racemic-2-(2-Hydroxyethyl)-6-nitro-3-oxo-4-(p-methoxybenzyl)-benz[1,4]oxazine. MS (m/e): 357 (MH⁺).

7.2.3 Racemic-2-2-Methanesulfonylethyl)-6-nitro-3-oxo-4-p-methoxybenzyl-benz[1,4]oxazine

To solution of 640 mg racemic-2-(2-hydroxyethyl)-6-nitro-3-oxo-4-(p-methoxybenzyl)-benz[1,4]oxazine in THF (30 mL) and 1 mL DIEA at 0° C. was added 330 uL MsCl. The reaction mixture was stirred at 0° C. for 20 minutes, at room temperature for 3 hours and then concentrated. The resulting residue was partitioned between bicarbonate solution and EtOAc. The aqueous phase was extracted with EtOAc and the combined organics washed with water, brine then dried over MgSO₄. The solvent was removed in vacuo and the crude material purified by column chromatography (hexanes/EtOAc) to yield 1 g of the title compound. MS (m/e): 437 (MH⁺).

7.2.4 2-2-Cyclopropyl)-6-nitro-3-oxo-4-p-methoxybenzyl)-benz[1,4]oxazine

To solution of 500 mg racemic-2-(2-Methanesulfonylethyl)-6-nitro-3-oxo-4-(p-methoxybenzyl)-benz[1,4]oxazine in THF (30 mL) at −15° C. was slowly added (dropwise) 2.5 mL of a 1.0 M lithiumhexamethylsilylazide solution and the reaction mixture was stirred at −15° C. for 3 hour. The reaction mixture was concentrated and the resulting residue was partitioned between bicarbonate solution and EtOAc. The aqueous phase was extracted with EtOAc and the combined organics washed with water, brine then dried over MgSO4. The solvent was removed in vacuo and the crude material purified by column chromatography (hexanes/EtOAc) to yield 150 mg of the desired product 2-2-cyclopropyl)-6-nitro-3-oxo-4-(p-methoxybenzyl)-benz[1,4]oxazine MS (m/e): 341 (MH⁺).

7.2.5 2-(2-Cyclopropyl)-6-nitro-3-oxo-4H-benz[1,4]oxazine

To solution of 400 mg 2-(2-cyclopropyl)-6-nitro-3-oxo-4-(p-methoxybenzyl)-benz[1,4]oxazine in acetonitrile/water (50 mL) was added 2.5 eq of ceric ammonium nitrate. The reaction mixture was stirred at ambient temperature for 18 hour, filtered, concentrated and the resulting residue partitioned between bicarbonate solution and EtOAc. The aqueous phase was extracted with EtOAc and the combined organics washed with water, brine and then dried over MgSO₄. The solvent was removed in vacuo and the crude material purified by column chromatography (hexanes/EtOAc) to yield 250 mg of the desired product 2-(2-cyclopropyl)-6-nitro-3-oxo-4H-benz[1,4]oxazine. MS (m/e): 341 (MH⁺).

7.2.6 6-Amino-2-(2-cycloproply)-3-oxo-4H-benz[1,4]oxazine

To a solution of 200 mg of 2-(2-cyclopropyl)-6-nitro-3-oxo-4H-benz[1,4]oxazine (1 g) in EtOH/water (20 mL; 2:1 v/v) was added 5 eq of iron and 5 eq of ammonium chloride and the reaction was heated at 90° C. for 4 h. The reaction mixture was cooled to room temperature, diluted with dichloromethane and filtered. The layers were separated, the aqueous was extracted once with dichloromethane, the combined organics layers were dried over magnesium sulfate, the solution filtered and the filtrate evaporated in vacuo to give the desired product 6-amino-2-(2-cycloproply)-3-oxo-4H-benz[1,4]. MS (m/e): 191 (MH⁺).

7.2.7 Pyrogallol 1-Benzenesulphonate 2,3-Dimethyl Ether

To solution of 10 mL 2,3-dimethoxyphenol and 13.3 mL TEA in 150 mL DCM at 0° C. was added 11.25 mL benzenesulphonyl chloride slowly dropwise with stirring. The reaction mixture was allowed to warm to room temperature and stirred overnight. The reaction mixture was filtered an the volume was reduce by rotary evaporation. The DCM solution was washed with dilute HCl solution, 50% saturated bicarbonate solution then brine, dried with magnesium sulfate, filtered and the solvent evaporated to yield 11 g of the desired product pyrogallol 1-benzenesulphonate 2,3-dimethy ether. MS (m/e): 295 (MH⁺).

7.2.8 5-Nitro Pyrogallol 1-Benzenesulphonate 2,3-Dimethyl Ether

To solution of 6.26 g of pyrogallol 1-benzenesulphonate 2,3-dimethy ether in 60 mL of glacial acetic acid at 0° C. was added 12 mL of fuming nitric acid. The reaction mixture was allowed to warm to room temperature and stirred overnight and then added to 400 mL of ice water. The solution was neutralized with solid sodium bicarbonate and extracted with ethyl acetate. The combined organics were washed with saturated bicarbonate solution, brine, dried ove magnesium sulfate, filtered and evaporated and the resulting residue was purified by silica gel column chromatography (hexanes/EtOAc 85:15) to yield 6 g of the desired product 5-nitro pyrogallol 1-benzenesulphonate 2,3-dimethyl ether. MS (m/e): 340 (MH⁺).

7.2.9 2,3-Dimethoxy-5-nitrophenol

A suspension of 6 g of (±)-5-nitro pyrogallol 1-benzenesulphonate 2,3-dimethyl ether in 60 mL of methanol and 36 mL 20% by weight KOH aqueous solution was heated at 50 degrees Celcius for 30 minutes with stirring then cooled, diluted with 350 mL D.I. water and acidified with excess conc. HCl to yield a precipitate that was collected by suction filtration and dried to yield 4.6 g of the desired product 2,3-dimethoxy-5-nitrophenol. MS (m/e): 200 (MH⁺).

7.2.10 4,5-Dimethoxy-3-hydroxyaniline

A solution of 1.1 g of 2,3-dimethoxy-5-nitrophenol in 45 mL dry methanol with 200 mg of 10% Pd/C (Degussa) was hydrogenated under a hydrogen ballon overnight. The reaction was filtered through a bed of celite and evaporated and the residue was chromatographed over silica gel (ethyl acetate/hexanes 3:2 gradient to 100% ethyl acetate). The appropriate fractions were evaporated to dryness to yield an oil that was taken up in methanol to which methanolic HCl solution was added and the solvent evaporated to yield 1.0 g of the desired product 4,5-dimethoxy-3-hydroxyaniline hydrochloride. MS (m/e): 170 (MH⁺).

7.2.11 2-Chloro-N-4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-4-pyrimidineamine

A mixture of 325 mg of 2,4-dichloro-5-fluoropyrimidine and 124 mg of 6-amino-2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazine in 20 mL 1:1 methanol/water was heated overnight at 80° C. and upon cooling was diluted with 1 N HCl solution. The precipitate was collected by suction filtration, dried, triturated with hexanes and dried again to yield 170 mg of the desired product 2-chloro-N-4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-4-pyrimidineamine ¹H NMR (DMSO-d6): δ 8.24 (d, 1H), 7.22 (d, 1H), 7.19(dd, 1H), 6.83 (d, 2H), 1.20 (m, 2H); LCMS: retention time 11.30 min; purity 94%; MS (m/e): 321 (MH⁺).

7.2.12 N4-[2-(2-Cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-[3-(N-methylamino)carbonylmethyleneoxyphenyl]-2,4-pyrimidinediamine (Compound 1)

A mixture of 40 mg of 2-Chloro-N-4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-4-pyrimidineamine and 48 mg of 3-(N-methylamino)carbonylmethyleneoxyaniline in 700 uL EtOH was heated in the microwave at 180° C. for 4200 seconds. The precipitate formed was collected by suction filtration, dried, suspended in a dilute bicarbonate solution, sonicated, recollected by suction filtration and dried to yield 25 mg of the desired product N4-[2-(2-Cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-[3-(N-methylamino)carbonylmethyleneoxyphenyl]-2,4-pyrimidinediamine ¹H NMR (DMSO-d6): δ 8.08(d, 1H), 7.92 (m, 1H), 7.32 (m, 4H), 7.04 (t, 1H), 6.81 (d, 1H), 6.43 (dd, 1H), 4.33 (s, 2H), 2.62 (d, 3H), 1.19 (m, 4H); LCMS: retention time 9.35 min; purity 96%; MS (m/e): 465 (MH⁺).

7.2.13 N4-[2-(2-Cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-(indazol-6-yl)-2,4-pyrimidinediamine (Compound 2)

In like manner to the preparation of N4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-[3-(N-methylamino)carbonylmethyleneoxyphenyl]-2,4-pyrimidinediamine, 2-chloro-N-4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-4-pyrimidineamine and 6-aminoindazole were reacted to yield the desired product N4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-(indazol-6-yl)-2,4-pyrimidinediamine. ¹H NMR (DMSO-d6): δ 8.06 (m, 2H), 7.82 (s, 1H), 7.53 (d, 4H), 7.39 (dd, 1H), 7.22 (m, 2H), 6.83(d, 1H), 1.19 (m, 4H); LCMS: retention time 9.29 min; purity 90%; MS (m/e): 418 (MH⁺).

7.2.14 N4-[2-(2-Cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-(3-hydroxyphenyl)-2,4-pyrimidinediamine (Compound 3)

In like manner to the preparation of N4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-[3-(N-methylamino)carbonylmethyleneoxyphenyl]-2,4-pyrimidinediamine, 2-chloro-N-4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-4-pyrimidineamine and 3-hydroxyaniline were reacted to yield the desired product N4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-(3-hydroxyphenyl)-2,4-pyrimidinediamine. ¹H NMR (DMSO-d6): δ8.09 (d, 1H), 7.23 (m, 2H), 7.01 (m, 3H), 6.82 (d, 1H), 6.39 (m, 1H), 1.20 (m, 4H); LCMS: retention time 9.30 min; purity 96%; MS (m/e): 394 (MH⁺).

7.2.15 N4-[2-(2-Cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine (Compound 4)

In like manner to the preparation of N4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-[3-(N-methylamino)carbonylmethyleneoxyphenyl]-2,4-pyrimidinediamine, 2-chloro-N-4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-4-pyrimidineamine and 3,4,5-trimethoxyaniline were reacted to yield the desired product N4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N2-(3,4,5-trimethoxyphenyl)-2,4-pyrimidinediamine. ¹H NMR (DMSO-d6): δ 8.12 (d, 1H), 7.21 (m, 2H), 6.87 (s, 2H), 6.77 (d, 1H), 3.58 (s, 6H), 3.56 (S, 3H), 1.20 (m, 4H); LCMS: retention time 10.25 min; purity 96.5%; MS (m/e): 468 (MH⁺).

7.2.16 N4-[2-(2-Cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-(3,4-dimethoxy-5-hydroxyphenyl)-2,4-pyrimidinediamine (Compound 5)

In like manner to the preparation of N4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-[3-(N-methylamino)carbonylmethyleneoxyphenyl]-2,4-pyrimidinediamine, 2-chloro-N-4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-4-pyrimidineamine and, 5-dimethoxy-3-hydroxyaniline hydrochloride were reacted to yield the desired product N4-[2-(2-cyclopropyl)-3-oxo-4H-benz[1,4]oxazin-6-yl]-5-fluoro-N-2-(3-hydroxy-4,5-trimethoxyphenyl)-2,4-pyrimidinediamine. ¹H NMR (DMSO-d6): δ 8.22 (s, 1H), 8.02 (d, 2H), 7.33 (m, 2H), 6.83 (m, 3H), 3.56 (S, 6H), 1.20 (m, 4H); purity 99%; MS (m/e): 454 (MH⁺).

7.3 Assays for Determining Whether Spiro 2,4-Pyrimidinediamine Compounds Inhibit FcεRI Receptor-Mediated Degranulation

The ability of spiro 2,4-pyrimidinediamine compounds to inhibit IgE-induced degranulation may be demonstrated in a variety of cellular assays with cultured human mast cells (CHMC) and/or mouse bone marrow derived cells (BMMC). Inhibition of degranulation is measured at both low and high cell density by quantifying the release of the granule specific factors tryptase, histamine and hexosaminidase. Inhibition of release and/or synthesis of lipid mediators is assessed by measuring the release of leukotriene LTC4 and inhibition of release and/or synthesis of cytokines was monitored by quantifying TNFα, IL-6 and IL-13. Tryptase and hexosaminidase are quantified using fluorogenic substrates as described in their respective examples. Histamine, TNFα, IL-6, IL-13 and LTC4 are quantified using the following commercial ELISA kits: histamine (Immunotech #2015, Beckman Coulter), TNFα (Biosource #KHC3011), IL-6 (Biosource #KMC0061), IL-13 (Biosource #KHC0132) and LTC4 (Cayman Chemical #520211). The protocols of the various assays are provided below.

7.3.1 Culturing of Human Mast and Basophil Cells

Human mast and basophil cells are cultured from CD34-negative progenitor cells as described below (see also the methods described in copending U.S. application Ser. No. 10/053,355, filed Nov. 8, 2001).

7.3.2 Preparation of STEMPRO-34 Complete Medium

To prepare STEMPRO-34 complete medium (“CM”), 250 mL STEMPRO-34′ serum free medium (“SFM”; GibcoBRL, Catalog No. 10640) is added to a filter flask. To this is added 13 mL STEMPRO-34 Nutrient Supplement (“NS”; GibcoBRL, Catalog No. 10641) (prepared as described in more detail, below). The NS container is rinsed with approximately 10 mL SFM and the rinse is added to the filter flask. Following addition of 5 mL L-glutamine (200 mM; Mediatech, Catalog No. MT 25-005-CI and 5 mL 100×penicillin/streptomycin (“pen-strep”; HyClone, Catalog No. SV30010), the volume is brought to 500 mL with SFM and the solution is filtered.

The most variable aspect of preparing the CM is the method by which the NS is thawed and mixed prior to addition to the SFM. The NS should be thawed in a 37° C. water bath and is swirled, not vortexed or shaken, until it is completely in solution. While swirling, take note whether there are any lipids that are not yet in solution. If lipids are present and the NS is not uniform in appearance, return it to the water bath and repeat the swirling process until it is uniform in appearance. Sometimes this component goes into solution immediately, sometimes after a couple of swirling cycles, and sometimes not at all. If, after a couple of hours, the NS is still not in solution, discard it and thaw a fresh unit. NS that appears non-uniform after thaw should not be used.

7.3.3 Expansion of CD34+Cells

A starting population of CD34-positive (CD34+) cells of relatively small number (1-5×10⁶ cells) is expanded to a relatively large number of CD34-negative progenitor cells (about 2-4×10⁹ cells) using the culture media and methods described below. The CD34+cells (from a single donor) are obtained from Allcells (Berkeley, Calif.). Because there is a degree of variation in the quality and number of CD34+ cells that Allcells typically provides, the newly delivered cells are transferred to a 15 mL conical tube and brought up to 10 mL in CM prior to use.

On day 0, a cell count is performed on the viable (phase-bright) cells and the cells were spun at 1200 rpm to pellet. The cells are resuspended to a density of 275,000 cells/mL with CM containing 200 ng/mL recombinant human Stem Cell Factor (“SCF”; Peprotech, Catalog No. 300-07) and 20 ng/mL human flt-3 ligand (Peprotech, Catalog No. 300-19) (“CM/SCF/flt-3 medium”). On about day 4 or 5, the density of the culture is checked by performing a cell count and the culture is diluted to a density of 275,000 cells/mL with fresh CM/SCF/flt-3 medium. On about day 7, the culture is transferred to a sterile tube and a cell count is performed. The cells are spun at 1200 rpm and resuspended to a density of 275,000 cells/mL with fresh CM/SCF/flt-3 medium.

This cycle is repeated, starting from day 0, a total of 3-5 times over the expansion period.

When the culture is large and being maintained in multiple flasks and is to be resuspended, the contents of all of the flasks are combined into a single container prior to performing a cell count. This ensures that an accurate cell count is achieved and provides for a degree of uniformity of treatment for the entire population. Each flask is checked separately for contamination under the microscope prior to combining to prevent contamination of the entire population.

Between days 17-24, the culture can begin to go into decline (i.e., approximately 5-10% of the total number of cells die) and fail to expand as rapidly as before. The cells are then monitored on a daily basis during this time, as complete failure of the culture can take place in as little as 24 hours. Once the decline has begun, the cells are counted, spun down at 850 rpm for 15 minutes, and resuspended at a density of 350,000 cells/mL in CM/SCF/flt-3 medium to induce one or two more divisions out of the culture. The cells are monitored daily to avoid failure of the culture.

When greater than 15% cell death is evident in the progenitor cell culture and some debris is present in the culture, the CD34-negative progenitor cells are ready to be differentiated.

7.3.4 Differentiation of CD34-Negative Progenitor Cells into Mucosal Mast Cells

A second phase is performed to convert the expanded CD34-negative progenitor cells into differentiated mucosal mast cells. These mucosal cultured human mast cells (“CHMC”) are derived from CD34+ cells isolated from umbilical cord blood and treated to form a proliferated population of CD34-negative progenitor cells, as described above. To produce the CD43-negative progenitor cells, the resuspension cycle for the culture is the same as that described above, except that the culture is seeded at a density of 425,000 cells/mL and 15% additional media is added on about day four or five without performing a cell count. Also, the cytokine composition of the medium is modified such that it contained SCF (200 ng/mL) and recombinant human IL-6 (200 ng/mL; Peprotech, Catalog No. 200-06 reconstituted to 100 ug/mL in sterile 10 mM acetic acid) (“CM/SCF/IL-6 medium”).

Phases I and II together span approximately 5 weeks. Some death and debris in the culture is evident during weeks 1-3 and there is a period during weeks 2-5 during which a small percentage of the culture is no longer in suspension, but is instead attached to the surface of the culture vessel.

As during Phase I, when the culture is to be resuspended on day seven of each cycle, the contents of all flasks are combined into a single container prior to performing a cell count to ensure uniformity of the entire population. Each flask is checked separately for contamination under the microscope prior to combining to prevent contamination of the entire population.

When the flasks are combined, approximately 75% of the volume is transferred to the communal container, leaving behind about 10 mL or so in the flask. The flask containing the remaining volume is rapped sharply and laterally to dislodge the attached cells. The rapping is repeated at a right angle to the first rap to completely dislodge the cells.

The flask is leaned at a 45 degree angle for a couple of minutes before the remaining volume is transferred to the counting vessel. The cells were spun at 950 rpm for 15 min prior to seeding at 35-50 mL per flask (at a density of 425,000 cells/mL).

7.3.5 Differentiation of CD34-Negative Progenitor Cells into Connective Tissue-Type Mast Cells

A proliferated population of CD34-negative progenitor cells is prepared as above and treated to form a tryptase/chymase positive (connective tissue) phenotype. The methods are performed as described above for mucosal mast cells, but with the substitution of IL-4 for IL-6 in the culture medium. The cells obtained are typical of connective tissue mast cells.

7.3.6 Differentiation of CD34-Negative Progenitor Cells into Basophil Cells

A proliferated population of CD34-negative progenitor cells is prepared as described in Section 7.2.1.3, above and used to form a proliferated population of basophil cells. The CD34-negative cells are treated as described for mucosal mast cells, but with the substitution of IL-3 (at 20-50 ng/mL) for IL-6 in the culture medium.

7.3.7 CHMC Low Cell Density IgE Activation: Tryptase and LTC4 Assays

To duplicate 96-well U-bottom plates (Costar 3799) add 65 ul of compound dilutions or control samples that have been prepared in MT [137 mM NaCl, 2.7 mM KCl, 1.8 mM CaCl₂, 1.0 mM MgCl₂, 5.6 mM Glucose, 20 mM Hepes (pH 7.4), 0.1% Bovine Serum Albumin, (Sigma A4503)] containing 2% MeOH and 1% DMSO. Pellet CHMC cells (980 rpm, 10 min) and resuspend in pre-warmed MT. Add 65 ul of cells to each 96-well plate. Depending on the degranulation activity for each particular CHMC donor, load 1000-1500 cells/well. Mix four times followed by a 1 hr incubation at 37° C. During the 1 hr incubation, prepare 6× anti-IgE solution [rabbit anti-human IgE (1 mg/ml, Bethyl Laboratories A80-109A) diluted 1:167 in MT buffer]. Stimulate cells by adding 25 ul of 6× anti-IgE solution to the appropriate plates. Add 25 ul MT to un-stimulated control wells. Mix twice following addition of the anti-IgE. Incubate at 37° C. for 30 minutes. During the 30 minute incubation, dilute the 20 mM tryptase substrate stock solution [(Z-Ala-Lys-Arg-AMC2TFA; Enzyme Systems Products, #AMC-246)] 1:2000 in tryptase assay buffer [0.1 M Hepes (pH 7.5), 10% w/v Glycerol, 10 uM Heparin (Sigma H-4898) 0.01% NaN₃]. Spin plates at 1000 rpm for 10 min to pellet cells. Transfer 25 ul of supernatant to a 96-well black bottom plate and add 100 ul of freshly diluted tryptase substrate solution to each well. Incubate plates at room temperature for 30 min. Read the optical density of the plates at 355 nm/460 nm on a spectrophotometric plate reader.

Leukotriene C4 (LTC4) is also quantified using an ELISA kit on appropriately diluted supernatant samples (determined empirically for each donor cell population so that the sample measurement falls within the standard curve) following the supplier's instructions.

7.3.8 CHMC High Cell Density IgE Activation: Degranulation (Tryptase, Histamine), Leukotriene (LTC4), and Cytokine (TNFalpha, IL-13) Assays

Cultured human mast cells (CHMC) are sensitized for 5 days with IL-4 (20 ng/ml), SCF (200 ng/ml), IL-6 (200 ng/ml), and Human IgE (CP 1035K from Cortx Biochem, 100-500 ng/ml depending on generation) in CM medium. After sensitizing, cells are counted, pelleted (1000 rpm, 5-10 minutes), and resuspended at 1-2×106 cells/ml in MT buffer. Add 100 ul of cell suspension to each well and 100 ul of compound dilutions. The final vehicle concentration is 0.5% DMSO. Incubate at 37□C (5% CO2) for 1 hour. After 1 hour of compound treatment, stimulate cells with 6× anti-IgE. Mix wells with the cells and allow plates to incubate at 37□C (5% CO2) for one hour. After 1 hour incubation, pellet cells (10 minutes, 1000 RPM) and collect 200 ul per well of the supernatant, being careful not to disturb pellet. Place the supernatant plate on ice. During the 7-hour step (see next) perform tryptase assay on supernatant that had been diluted 1:500. Resuspend cell pellet in 240 ul of CM media containing 0.5% DMSO and corresponding concentration of compound. Incubate CHMC cells for 7 hours at 37° C. (5% CO₂). After incubation, pellet cells (1000 RPM, 10 minutes) and collect 225 ul per well and place in −80° C. until ready to perform ELISAS. ELISAS are performed on appropriately diluted samples (determined empirically for each donor cell population so that the sample measurement falls within the standard curve) following the supplier's instructions.

7.4 The 2,4-Pyrimidinediamine Compounds of the Invention May Selectively Inhibit the Upstream IgE Receptor Cascade

The spiro 2,4-pyrimidinediamine compounds may be tested in cellular assays for ionomycin-induced degranulation, as described below, to determine if they are blocking or inhibiting the early IgE receptor signal transduction cascade.

7.4.1 CHMC Low Cell Density Ionomycin Activation: Tryptase Assay

Assays for ionomycin-induced mast cell degranulation are carried out as described for the CHMC Low Density IgE Activation assays (Section 7.2.2, supra), with the exception that during the 1 hour incubation, 6× ionomycin solution [5 mM ionomycin (Sigma 1-0634) in MeOH (stock) diluted 1:416.7 in MT buffer (2 □M final)] is prepared and cells are stimulated by adding 25 μl of the 6× ionomycin solution to the appropriate plates.

7.5 The Spiro 2,4-Pyrimidinediamine Compounds Inhibit the IgE Receptor Signalling Cascade

Compounds 1-5 were tested for their ability to inhibit the IgE receptor signaling cascade in an 8-point assay with CHMC cells. For the assay the amount of tryptase release was measured. All five compounds exhibited IC₅₀'s of less than 100 nM.

7.6 2,4-Pyrimidinediamine Compounds Inhibit Syk Kinase in Biochemical Assays

The spiro 2,4-pyrimidinediamine compounds can be tested for the ability to inhibit Syk kinase catalyzed phosphorylation of a peptide substrate in a biochemical fluorescence polarization assay with isolated Syk kinase. In this experiment, compounds are diluted to 1% DMSO in kinase buffer (20 mM HEPES, pH 7.4, 5 mM MgCl₂, 2 mM MnCl₂, 1 mM DTT, 0.1 mg/mL acetylated Bovine Gamma Globulin). Compounds in 1% DMSO (0.2% DMSO final) are mixed with ATP/substrate solution at room temperature. Syk kinase (Upstate, Lake Placid N.Y.) is added to a final reaction volume of 20 uL, and the reaction is incubated for 30 minutes at room temperature. Final enzyme reaction conditions are 20 mM HEPES, pH 7.4, 5 mM MgCl₂, 2 mM MnCl₂, 1 mM DTT, 0.1 mg/mL acetylated Bovine Gamma Globulin, 0.125 ng Syk, 4 uM ATP, 2.5 uM peptide substrate (biotin-EQEDEPEGDYEEVLE-CONH2, SynPep Corporation). EDTA (10 mM final)/anti-phosphotyrosine antibody (1× final)/fluorescent phosphopeptide tracer (0.5× final) is added in FP Dilution Buffer to stop the reaction for a total volume of 40 uL according to manufacturer's instructions (PanVera Corporation). The plate is incubated for 30 minutes in the dark at room temperature. Plates are read on a Polarion fluorescence polarization plate reader (Tecan). Data was converted to an amount of phosphopeptide present using a calibration curve generated by competition with the phosphopeptide competitor provided in the Tyrosine Kinase Assay Kit, Green (PanVera Corporation).

Compounds 1-4 were tested in this assay. All compounds exhibited an IC₅₀ of Syk inhibition of less than 125 nM.

7.7 The In Vivo Efficacy of Compounds Towards Autoimmune Diseases May be Demonstrated in a Mouse Model of Collagen Antibody-Induced Arthritis (CAIA).

7.7.1 Model

Collagen-induced arthritis (CIA) in rodents is frequently used as one of the experimental models for IC-mediated tissue injury. Administration of type II collagen into mice or rats results in an immune reaction that characteristically involves inflammatory destruction of cartilage and bone of the distal joints with concomitant swelling of surrounding tissues. CIA is commonly used to evaluate compounds that might be of potential use as drugs for treatment of rheumatoid arthritis and other chronic inflammatory conditions.

In recent years, a new technique emerged in CIA modeling, in which the anti-type II collagen antibodies are applied to induce an antibody-mediated CIA. The advantages of the method are: Short time for induction of disease (developing within 24-48 hrs after an intravenous (IV) injection of antibodies); arthritis is inducible in both CIA-susceptible and CIA-resistant mouse strains; and the procedure is ideal for rapid screening of anti-inflammatory therapeutic agents.

Arthrogen-CIA® Arthritis-inducing Monoclonal Antibody Cocktail (Chemicon International Inc.) is administered intravenously to Balb/c mice (2 mg/mouse) on Day 0. Forty-eight hours later, 100 μl of LPS (25 μg) is injected intraperitoneally. On Day 4, toes may appear swollen. By Day 5, one or two paws (particular the hind legs) begin to appear red and swollen. On Day 6, and thereafter, red and swollen paws will remain for at least 1-2 weeks. During the study, the clinical signs of inflammation are scored to evaluate the intensity of edema in the paws. The severity of arthritis is recorded as the sum score of both hind paws for each animal (possible maximum score of 8). The degree of inflammation with involved paws is evaluated by measurement of diameter of the paws. Body weight changes are monitored.

Animals can be treated at the time of induction of arthritis, beginning on Day 0. Test compounds and control compounds can be administered once a day (q.d.) or twice a day (b.i.d.), via per os (PO), depending on previously established PK profiles.

At the end of the study (1-2 weeks after induction of arthritis), mice are euthanized and the paws are transected at the distal tibia using a guillotine and weighed. The mean±standard error of the mean (SEM) for each group is determined each day from individual animal clinical scores, and hind paw weights for each experimental group are calculated and recorded at study termination. Histopathological evaluation of paws are obtained.

7.7.2 Results

Reduced inflammation and swelling should be evident in animals treated with compounds described herein, and the arthritis would progress more slowly. Treatment with compounds should (b.i.d.) significantly reduce clinical arthritis compared with animals treated with vehicle only.

7.8 The Compounds Can Be Effective In Rat Collagen-Induced Arthritis

The in vivo efficacy of compounds described herein towards autoimmune diseases can be demonstrated in a rat model of collagen-induced arthritis (CIA).

7.8.1 Model Description

Rheumatoid arthritis (RA) is characterized by chronic joint inflammation eventually leading to irreversible cartilage destruction. IgG-containing IC are abundant in the synovial tissue of patients with RA. While it is still debated what role these complexes play in the etiology and pathology of the disease, IC communicate with the hematopoetic cells via the FcγR.

CIA is a widely accepted animal model of RA that results in chronic inflammatory synovitis characterized by pannus formation and joint degradation. In this model, intradermal immunization with native type II collagen, emulsified with incomplete Freund's adjuvant, results in an inflammatory polyarthritis within 10 or 11 days and subsequent joint destruction in 3 to 4 weeks.

7.8.2 Study Protocol

Syngeneic LOU rats are immunized on Day 0 with native chicken CII/IFA (performed at UCLA; E. Brahn, Principal Investigator). Beginning on the day of arthritis onset (Day 10), a total of 59 rats are treated with either a vehicle control or a compound described herein at one of four dose levels (1, 3, 10, and 30 mg/kg, q.d. by p.o. gavage).

7.8.3 Results

Hind limbs are scored daily for clinical arthritis severity using a standardized method based on the degree of joint inflammation. High resolution digital radiographs of hind limbs can be obtained at the conclusion of the study (Day 28). These limbs can also be analyzed for histopathologic changes. IgG antibodies to native CII can be measured in quadruplicate by ELISA.

Although the foregoing invention has been described in some detail to facilitate understanding, it will be apparent that certain changes and modifications may be practiced within the scope of the appended claims. Accordingly, the described embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

All literature and patent references cited throughout the application are incorporated by reference into the application for all purposes in their entirety. 

1. A compound according to structural formula (I):

including salts, hydrates, solvates and N-oxides thereof, wherein: L¹ is a direct bond or a linker; L² is a direct bond or a linker; R² is selected from the group consisting of (C1-C6) alkyl optionally substituted with one or more of the same or different R⁸ groups, (C3-C8) alkyl optionally substituted with one or more of the same or different R⁸ groups, 3-8 membered cycloheteroalkyl optionally substituted with one or more of the same or different R⁸ groups, (C5-C15) aryl optionally substituted with one or more of the same or different R⁸ groups, phenyl optionally substituted with one or more of the same or different R⁸ groups and 5-15 membered heteroaryl optionally substituted with one or more of the same or different R⁸ groups; R⁴ is

each W is, independently of the other, —CR³¹R³¹—; X is selected from the group consisting of —N— and —CH—; Y and Z are each, independently of one another, selected from the group consisting of —O—, —S—, —SO—, —SO₂—, —SONR³⁶—, —NH—, —NR³⁵— and —NR³⁷—; R⁵ is selected from the group consisting of hydrogen, an electronegative group, —OR^(d), —SR^(d), (C1-C3) haloalkyloxy, (C1-C3) perhaloalkyloxy, —NR^(c)R^(c), halogen, (C1-C3) haloalkyl, (C1-C3) perhaloalkyl, —CF₃, —CH₂CF₃, —CF₂CF₃, —CN, —NC, —OCN, —SCN, —NO, —NO₂, —N₃, —S(O)R^(d), —S(O)₂R^(d), —S(O)₂OR^(d), —S(O)NR^(c)R^(c); —S(O)₂NRCR^(c), —OS(O)R^(d), —OS(O)₂R^(d), —OS(O)₂OR^(d), —OS(O)NR^(c)R^(c), —OS(O)₂NR^(c)R^(c), —C(O)R^(d), —C(O)OR^(d), —C(O)NR^(c)R^(c), —C(NH)NR^(c)R^(c), —OC(O)R^(d), —SC(O)R^(d), —OC(O)OR^(d), —SC(O)OR^(d), —OC(O)NR^(c)R^(c), —SC(O)NR^(c)R^(c), —OC(NH)NR^(c)R^(c), —SC(NH)NR^(c)R^(c), —[NHC(O)]_(n)R^(d), —[NHC(O)]_(n)OR^(d), —[NHC(O)]_(n)NR^(c)R^(c) and —[NHC(NH)]_(n)NR^(c)R^(c), (C5-C10) aryl optionally substituted with one or more of the same or different R⁸ groups, phenyl optionally substituted with one or more of the same or different R⁸ groups, (C6-C16) arylalkyl optionally substituted with one or more of the same or different R⁸ groups, 5-10 membered heteroaryl optionally substituted with one or more of the same or different R⁸ groups and 6-16 membered heteroarylalkyl optionally substituted with one or more of the same or different R⁸ groups, (C1-C6) alkyl optionally substituted with one or more of the same or different R⁸ groups, (C1-C4) alkanyl optionally substituted with one or more of the same or different R⁸ groups, (C2-C4) alkenyl optionally substituted with one or more of the same or different R⁸ groups and (C2-C4) alkynyl optionally substituted with one or more of the same or different R⁸ groups; R⁶ independently is selected from the group consisting of hydrogen, an electronegative group, —OR^(d), —SR^(d), (C1-C3) haloalkyloxy, (C1-C3) perhaloalkyloxy, —NR^(c)R^(c), halogen, (C1-C3) haloalkyl, (C1-C3) perhaloalkyl, —CF₃, —CH₂CF₃, —CF₂CF₃, —CN, —NC, —OCN, —SCN, —NO, —NO₂, —N₃, —S(O)R^(d), —S(O)₂R^(d), S(O)₂OR^(d), —S(O)NR^(c)R^(c); —S(O)₂NR^(c)R^(c), —OS(O)R^(d), —OS(O)₂R^(d), —OS(O)₂OR^(d), —OS(O)NR^(c)R^(c), —OS(O)₂NR^(c)R^(c), —C(O)R^(d), —C(O)OR^(d), —C(O)NR^(c)R^(c), —C(NH)NR^(c)R^(c), —OC(O)R^(d), —SC(O)R^(d), —OC(O)OR^(d), —SC(O)OR^(d), —OC(O)NR^(c)R^(c), —SC(O)NR^(c)R^(c), —OC(NH)NR^(c)R^(c), —SC(NH)NR^(c)R^(c), —[NHC(O)]_(n)R^(d), —[NHC(O)]_(n)OR^(d), —[NHC(O)]_(n)NR^(c)R^(c) and —[NHC(NH)]_(n)NR^(c)R^(c), (C5-C10) aryl optionally substituted with one or more of the same or different R⁸ groups, phenyl optionally substituted with one or more of the same or different R⁸ groups, (C6-C16) arylalkyl optionally substituted with one or more of the same or different R⁸ groups, 5-10 membered heteroaryl optionally substituted with one or more of the same or different R⁸ groups and 6-16 membered heteroarylalkyl optionally substituted with one or more of the same or different R⁸ groups; R⁸ is selected from the group consisting of R^(a), R^(b), R^(a) substituted with one or more of the same or different R^(a) or R^(b), —OR^(a) substituted with one or more of the same or different R^(a) or R^(b), —B(OR^(a))₂, —B(NR^(c)R^(c))₂, —(CH₂)_(m)—R^(b), —(CHR^(a))_(m)—R^(b), —O—(CH₂)_(m)—R^(b), —S—(CH₂)_(m)—R^(b), —O—CHR^(a)R^(b), —O—CR^(a)(R^(b))₂, —O—(CHR^(a))_(m)R^(b), —O— (CH₂)_(m)—CH[(CH₂)_(m)R^(b)]R^(b), —S—(CHR^(a))_(m)—R^(b), —C(O)NH—(CH₂)_(m)—R^(b), —C(O)NH—(CHR^(a))_(m)—R^(b), —O—(CH₂)_(m)—C(O)NH—(CH₂)_(m)—R^(b), —S—(CH₂)_(m)—C(O)NH—(CH₂)_(m)—R^(b), —O—(CHR^(a))_(m)—C(O)NH—(CHR^(a))_(m)—R^(b), —S—(CHR^(a))_(m)—C(O)NH—(CHR^(a))_(m)—R^(b), —NH—(CH₂)_(m)—R^(b), —NH—(CHR^(a))_(m)—R^(b), —NH[(CH₂)_(m)R^(b)], —N[(CH₂)_(m)R^(b)]₂, —NH—C(O)—NH—(CH₂)_(m)—R^(b), —NH—C(O)—(CH₂)_(m)—CHR^(b)R^(b) and —NH— (CH₂)_(m)—C(O)—NH—(CH₂)_(m)—R^(b); each R³¹ is, independently of the others, hydrogen or (C1-C6) alkyl optionally substituted with one or more of the same or different R⁸ groups; each R³⁵ is, independently of the other, selected from the group consisting of hydrogen and R⁸, or, alternatively, the two R³⁵ groups are taken together to form an oxo (═O), or ═NR³⁸ group; each R³⁶ is, independently of the others, selected from the group consisting of hydrogen and (C1-C6) alkyl; each R³⁷ is, independently of the others, selected from the group consisting of hydrogen and a progroup; R³⁸ is selected from the group consisting of hydrogen, (C1-C6) alkyl and (C5-C14) aryl; each R^(a) is, independently of the others, selected from the group consisting of hydrogen, (C1-C6) alkyl, (C3-C8) cycloalkyl, cyclohexyl, (C4-C11) cycloalkylalkyl, (C5-C10) aryl, phenyl, (C6-C16) arylalkyl, benzyl, 2-6 membered heteroalkyl, 3-8 membered cycloheteroalkyl, morpholinyl, piperazinyl, homopiperazinyl, piperidinyl, 4-11 membered cycloheteroalkylalkyl, 5-10 membered heteroaryl and 6-16 membered heteroarylalkyl; each R^(b) is, independently of the others, a suitable group independently selected from the group consisting of ═O, —OR^(d), (C1-C3) haloalkyloxy, —OCF₃, ═S, —SR^(d), ═NR^(d), ═NOR^(d), —NR^(c)R^(c), halogen, —CF₃, —CN, —NC, —OCN, —SCN, —NO, —NO₂, ═N₂, —N₃, —S(O)R^(d), —S(O)₂R^(d), —S(O)₂OR^(d), —S(O)NR^(c)R^(c), —S(O)₂NR^(c)R^(c), —OS(O)R^(d), —OS(O)₂R^(d), —OS(O)₂OR^(d), —OS(O)₂NR^(c)R^(c), —C(O)R^(d), —C(O)OR^(d), —C(O)NR^(c)R^(c), —C(NH)NR^(c)R^(c), —C(NR^(a))NR^(c)R^(c), —C(NOH)R^(a), —C(NOH)NR^(c)R^(c), —OC(O)R^(d), —OC(O)OR^(d), —C(O)NR^(c)R^(c), —OC(NH)NR^(c)R^(c), —OC(NR^(a))NR^(c)R^(c), —[NHC(O)]_(n)R^(d), —[NR^(a)C(O)]_(n)R^(d), —[NHC(O)]_(n)OR^(d), —[NR^(a)C(O)]_(n)OR^(d), —[NHC(O)]_(n)NR^(c)R^(c), —[NR^(a)C(O)]_(n)NR^(c)R^(c), —[NHC(NH)]_(n)NR^(c)R^(c) and —[NR^(a)C(NR^(a))]_(n)NR^(c)R^(c); each R^(c) is, independently or the others, a protecting group or R^(a), or, alternatively, each R^(c) is taken together with the nitrogen atom to which it is bonded to form a 5 to 8-membered cycloheteroalkyl or heteroaryl which may optionally include one or more of the same or different additional heteroatoms and which may optionally be substituted with one or more of the same or different R^(a) or suitable R^(b) groups; each R^(d) is, independently of the others, a protecting group or R^(a); each m is, independently of the others, an integer from 1 to 3; each n is, independently of the others, an integer from 0 to 3; and o is an integer from 1 to
 6. 2. The compound of claim 1 according to structural Formula (V):


3. The compound of claim 1 or claim 2 in which R⁵ is halo, fluoro or —CF₃.
 4. The compound of claim 1 or claim 2 in which R⁵ is fluoro.
 5. The compound of claim 1 or claim 2 in which R⁶ is hydrogen.
 6. The compound of claim 1 or claim 2 in which Y and Z are independently selected from the group consisting of O and NH.
 7. The compound of claim 1 or claim 2 in which X is —CH—.
 8. The compound of claim 1 or claim 2 in which each R³⁵ is hydrogen.
 9. The compound of claim 1 or claim 2 in which the two R³⁵ groups form an oxo group.
 10. The compound of claim 1 or claim 2 in which Y is O and Z is NH.
 11. The compound of claim 1 or claim 2 in which o is an integer from 1 to
 4. 12. The compound of claim 1 or claim 2 in which o is
 1. 13. The compound of claim 1 or claim 2 in which each R³¹ is independently hydrogen or (C1-C6) alkyl.
 14. The compound of claim 1 or claim 2 in which each R³¹ is hydrogen.
 15. The compound of claim 1 or claim 2 in which R² is phenyl optionally substituted with one or more of the same or different R⁸ groups.
 16. The compound of claim 1 or claim 2 in which R² is a disubstituted phenyl group with two R^(b) groups or R² is a trisubstituted phenyl group with three R^(b) groups.
 17. The compound of claim 1 or claim 2 in which R² is


18. The compound of claim 1 or claim 2 in which R⁵ is halo, fluoro or —CF₃ and R⁶ is hydrogen.
 19. The compound of claim 1 or claim 2 in which R⁵ is fluoro and R⁶ is hydrogen.
 20. The compound of claim 1 or claim 2 in which the two R³⁵ groups form an oxo group, Y is O, Z is NH, X is CH and each R³¹ is hydrogen.
 21. The compound of claim 20 in which R⁵ is fluoro and R⁶ is hydrogen.
 22. The compound of claim 21 in which R² is phenyl optionally substituted with one or more of the same or different R⁸ groups.
 23. The compound of claim 21 in which R² is a disubstituted phenyl group with two R^(b) groups or R² is a trisubstituted phenyl group with three R^(b) groups.
 24. The compound of claim 21 in which R² is


25. The compound of claim 21 in which o is
 1. 26. The compound of claim 25 in which R² is phenyl optionally substituted with one or more of the same or different R⁸ groups.
 27. The compound of claim 25 in which R² is a disubstituted phenyl group with two R^(b) groups or R² is a trisubstituted phenyl group with three R^(b) groups.
 28. The compound of claim 25 in which R² is


29. The compound of claim 1 or claim 2 further comprising a pharmaceutically acceptable carrier, diluent or excipient.
 30. A method of treating or preventing an autoimmune disease and/or one or more symptoms associated therewith, comprising the step of administering to a subject suffering from an autoimmune disease or at risk of developing an autoimmune disease an effective amount of a 2,4-pyrimidinediamine compound according to claim 1 or claim
 2. 